<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <meta name="aspect-ratio" content="4:3">
  <style>
    * {
      box-sizing: border-box;
      margin: 0;
      padding: 0;
    }

    body {
      background-color: #f8f9fa;
      font-family: system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
      color: #1e2945;
      display: flex;
      flex-direction: column;
      align-items: center;
      justify-content: center;
      padding: 12px;
      min-height: 100%;
    }

    .scale-container {
      width: 100%;
      max-width: 480px;
      position: relative;
    }

    svg {
      width: 100%;
      height: auto;
      display: block;
      overflow: visible;
    }

    .pan-label {
      font-size: 18px;
      font-weight: 800;
      fill: #1e2945;
      text-anchor: middle;
      dominant-baseline: central;
    }

    .badge-bg {
      fill: #ffffff;
      stroke: #e2e8f0;
      stroke-width: 1.5px;
      filter: drop-shadow(0 2px 4px rgba(0, 0, 0, 0.05));
    }

    .cards-row {
      display: flex;
      flex-direction: row;
      gap: 12px;
      width: 100%;
      max-width: 480px;
      margin-top: 14px;
    }

    .equation-card {
      flex: 1;
      background: #ffffff;
      border: 2px solid #e2e8f0;
      border-radius: 12px;
      padding: 10px 14px;
      display: flex;
      align-items: center;
      justify-content: center;
      gap: 8px;
      font-size: 18px;
      font-weight: 700;
      color: #1e2945;
      box-shadow: 0 2px 6px rgba(0, 0, 0, 0.04);
      cursor: pointer;
      user-select: none;
      transition: border-color 0.2s ease, box-shadow 0.2s ease, background-color 0.2s ease;
    }

    .equation-card:hover, .equation-card.active {
      border-color: #22b7ff;
      background-color: #f0f9ff;
      box-shadow: 0 4px 12px rgba(34, 183, 255, 0.15);
    }

    .check-icon {
      display: inline-flex;
      align-items: center;
      justify-content: center;
      width: 24px;
      height: 24px;
      background: #10b981;
      color: #ffffff;
      border-radius: 50%;
      font-size: 14px;
      font-weight: 900;
      flex-shrink: 0;
    }

    .purple-txt { color: #8b5cf6; }
    .blue-txt { color: #3b82f6; }
    .yellow-txt { color: #d97706; }
    .equal-txt { color: #64748b; margin: 0 2px; }

    @media (max-width: 380px) {
      .equation-card {
        font-size: 15px;
        padding: 8px 10px;
        gap: 6px;
      }
      .check-icon {
        width: 20px;
        height: 20px;
        font-size: 12px;
      }
    }
  </style>
</head>
<body>

  <div class="scale-container">
    <svg viewBox="0 0 460 215" aria-label="Balanced scale showing 5 blocks on left and 4 plus 1 blocks on right">
      
      <polygon points="230,125 198,198 262,198" fill="#64748b" rx="4"/>
      <rect x="180" y="195" width="100" height="10" rx="4" fill="#475569"/>

      
      <line x1="230" y1="125" x2="230" y2="195" stroke="#475569" stroke-width="3" stroke-linecap="round"/>

      
      <rect x="50" y="102" width="360" height="8" rx="4" fill="#334155"/>

      
      <circle cx="230" cy="106" r="15" fill="#22b7ff"/>
      <circle cx="230" cy="106" r="12" fill="#ffffff"/>
      <text x="230" y="106" font-size="16" font-weight="900" fill="#22b7ff" text-anchor="middle" dominant-baseline="central">=</text>

      
      
      <line x1="95" y1="108" x2="52" y2="168" stroke="#94a3b8" stroke-width="2"/>
      <line x1="95" y1="108" x2="138" y2="168" stroke="#94a3b8" stroke-width="2"/>

      
      <path d="M 45 168 Q 95 178 145 168 Z" fill="#cbd5e1" stroke="#94a3b8" stroke-width="1.5"/>

      
      
      <rect x="58" y="145" width="22" height="22" rx="4" fill="#8b5cf6" stroke="#7c3aed" stroke-width="1.5"/>
      <rect x="84" y="145" width="22" height="22" rx="4" fill="#8b5cf6" stroke="#7c3aed" stroke-width="1.5"/>
      <rect x="110" y="145" width="22" height="22" rx="4" fill="#8b5cf6" stroke="#7c3aed" stroke-width="1.5"/>
      
      <rect x="71" y="121" width="22" height="22" rx="4" fill="#8b5cf6" stroke="#7c3aed" stroke-width="1.5"/>
      <rect x="97" y="121" width="22" height="22" rx="4" fill="#8b5cf6" stroke="#7c3aed" stroke-width="1.5"/>

      
      <rect class="badge-bg" x="67" y="14" width="56" height="34" rx="8"/>
      <text class="pan-label" x="95" y="31" fill="#8b5cf6">5</text>
      
      <line x1="95" y1="48" x2="95" y2="92" stroke="#cbd5e1" stroke-width="1.5" stroke-dasharray="3,3"/>

      
      
      <line x1="365" y1="108" x2="322" y2="168" stroke="#94a3b8" stroke-width="2"/>
      <line x1="365" y1="108" x2="408" y2="168" stroke="#94a3b8" stroke-width="2"/>

      
      <path d="M 315 168 Q 365 178 415 168 Z" fill="#cbd5e1" stroke="#94a3b8" stroke-width="1.5"/>

      
      
      <rect x="328" y="145" width="22" height="22" rx="4" fill="#3b82f6" stroke="#2563eb" stroke-width="1.5"/>
      <rect x="354" y="145" width="22" height="22" rx="4" fill="#3b82f6" stroke="#2563eb" stroke-width="1.5"/>
      <rect x="380" y="145" width="22" height="22" rx="4" fill="#3b82f6" stroke="#2563eb" stroke-width="1.5"/>
      
      <rect x="341" y="121" width="22" height="22" rx="4" fill="#3b82f6" stroke="#2563eb" stroke-width="1.5"/>
      <rect x="367" y="121" width="22" height="22" rx="4" fill="#fbbf24" stroke="#d97706" stroke-width="1.5"/>

      
      <rect class="badge-bg" x="323" y="14" width="84" height="34" rx="8"/>
      <text class="pan-label" x="365" y="31">
        <tspan fill="#3b82f6">4</tspan>
        <tspan fill="#64748b" font-weight="600"> + </tspan>
        <tspan fill="#d97706">1</tspan>
      </text>
      
      <line x1="365" y1="48" x2="365" y2="92" stroke="#cbd5e1" stroke-width="1.5" stroke-dasharray="3,3"/>
    </svg>
  </div>

  <div class="cards-row">
    <div class="equation-card active" onclick="highlightCard(this)">
      <span>
        <span class="purple-txt">5</span>
        <span class="equal-txt">=</span>
        <span class="blue-txt">4</span><span class="equal-txt">+</span><span class="yellow-txt">1</span>
      </span>
      <span class="check-icon">✓</span>
    </div>

    <div class="equation-card" onclick="highlightCard(this)">
      <span>
        <span class="blue-txt">4</span><span class="equal-txt">+</span><span class="yellow-txt">1</span>
        <span class="equal-txt">=</span>
        <span class="purple-txt">5</span>
      </span>
      <span class="check-icon">✓</span>
    </div>
  </div>

  <script>
    function highlightCard(element) {
      document.querySelectorAll('.equation-card').forEach(card => card.classList.remove('active'));
      element.classList.add('active');
    }
  </script>
</body>
</html>

Understanding the Equal Sign Means "Same Value"

<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>Balance Scale Equations</title>
  <style>
    * {
      box-sizing: border-box;
      margin: 0;
      padding: 0;
    }
    body {
      font-family: system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
      color: #1e293b;
      background: transparent;
      display: flex;
      flex-direction: column;
      align-items: center;
      justify-content: center;
      min-height: 100vh;
      padding: 12px;
    }
    .diagram-container {
      display: flex;
      flex-direction: column;
      align-items: center;
      gap: 16px;
      width: 100%;
      max-width: 520px;
    }
    .scale-section {
      width: 100%;
      display: flex;
      flex-direction: column;
      align-items: center;
    }
    .equation-bar {
      display: flex;
      align-items: center;
      justify-content: center;
      gap: 10px;
      font-size: 20px;
      font-weight: 700;
      color: #0f172a;
      margin-bottom: 4px;
    }
    .eq-text {
      letter-spacing: 0.5px;
    }
    .check {
      display: inline-flex;
      align-items: center;
      justify-content: center;
      color: #15803d;
      font-size: 20px;
      font-weight: 900;
    }
    .scale-svg {
      width: 100%;
      max-width: 380px;
      height: auto;
      overflow: visible;
    }
    .caption {
      font-size: 15px;
      font-weight: 600;
      color: #065f46;
      background-color: #ecfdf5;
      padding: 8px 16px;
      border-radius: 8px;
      text-align: center;
      line-height: 1.4;
      max-width: 440px;
    }
    @media (max-width: 400px) {
      .equation-bar {
        font-size: 18px;
      }
      .check {
        font-size: 18px;
      }
      .caption {
        font-size: 13.5px;
        padding: 6px 12px;
      }
    }
  </style>
</head>
<body>

  <div class="diagram-container">
    
    <div class="scale-section">
      <div class="equation-bar">
        <span class="eq-text">4 + 2 = 6</span>
        <span class="check" aria-label="true">✓</span>
      </div>
      
      <svg class="scale-svg" viewBox="0 0 300 95" aria-label="Balance scale showing 4 plus 2 red dots balancing 6 red dots">
        
        <line x1="150" y1="50" x2="150" y2="82" stroke="#94a3b8" stroke-width="4" stroke-linecap="round"/>
        <polygon points="150,48 138,82 162,82" fill="#64748b"/>
        <circle cx="150" cy="50" r="4.5" fill="#334155"/>
        <line x1="118" y1="84" x2="182" y2="84" stroke="#475569" stroke-width="3.5" stroke-linecap="round"/>

        
        <line x1="45" y1="50" x2="255" y2="50" stroke="#334155" stroke-width="3.5" stroke-linecap="round"/>

        
        <line x1="45" y1="50" x2="28" y2="70" stroke="#94a3b8" stroke-width="1.5"/>
        <line x1="45" y1="50" x2="62" y2="70" stroke="#94a3b8" stroke-width="1.5"/>
        <path d="M 20 70 Q 45 76 70 70" fill="none" stroke="#475569" stroke-width="3" stroke-linecap="round"/>

        
        
        <circle cx="28" cy="64" r="3.6" fill="#dc2626"/>
        <circle cx="36" cy="64" r="3.6" fill="#dc2626"/>
        <circle cx="32" cy="57" r="3.6" fill="#dc2626"/>
        <circle cx="40" cy="57" r="3.6" fill="#dc2626"/>
        
        <circle cx="52" cy="64" r="3.6" fill="#ef4444"/>
        <circle cx="60" cy="64" r="3.6" fill="#ef4444"/>

        
        <line x1="255" y1="50" x2="238" y2="70" stroke="#94a3b8" stroke-width="1.5"/>
        <line x1="255" y1="50" x2="272" y2="70" stroke="#94a3b8" stroke-width="1.5"/>
        <path d="M 230 70 Q 255 76 280 70" fill="none" stroke="#475569" stroke-width="3" stroke-linecap="round"/>

        
        <circle cx="238" cy="64" r="3.6" fill="#dc2626"/>
        <circle cx="246" cy="64" r="3.6" fill="#dc2626"/>
        <circle cx="254" cy="64" r="3.6" fill="#dc2626"/>
        <circle cx="262" cy="64" r="3.6" fill="#dc2626"/>
        <circle cx="270" cy="64" r="3.6" fill="#dc2626"/>
        <circle cx="254" cy="57" r="3.6" fill="#dc2626"/>
      </svg>
    </div>

    
    <div class="scale-section">
      <div class="equation-bar">
        <span class="eq-text">6 = 4 + 2</span>
        <span class="check" aria-label="true">✓</span>
      </div>
      
      <svg class="scale-svg" viewBox="0 0 300 95" aria-label="Balance scale showing 6 red dots balancing 4 plus 2 red dots">
        
        <line x1="150" y1="50" x2="150" y2="82" stroke="#94a3b8" stroke-width="4" stroke-linecap="round"/>
        <polygon points="150,48 138,82 162,82" fill="#64748b"/>
        <circle cx="150" cy="50" r="4.5" fill="#334155"/>
        <line x1="118" y1="84" x2="182" y2="84" stroke="#475569" stroke-width="3.5" stroke-linecap="round"/>

        
        <line x1="45" y1="50" x2="255" y2="50" stroke="#334155" stroke-width="3.5" stroke-linecap="round"/>

        
        <line x1="45" y1="50" x2="28" y2="70" stroke="#94a3b8" stroke-width="1.5"/>
        <line x1="45" y1="50" x2="62" y2="70" stroke="#94a3b8" stroke-width="1.5"/>
        <path d="M 20 70 Q 45 76 70 70" fill="none" stroke="#475569" stroke-width="3" stroke-linecap="round"/>

        
        <circle cx="28" cy="64" r="3.6" fill="#dc2626"/>
        <circle cx="36" cy="64" r="3.6" fill="#dc2626"/>
        <circle cx="44" cy="64" r="3.6" fill="#dc2626"/>
        <circle cx="52" cy="64" r="3.6" fill="#dc2626"/>
        <circle cx="60" cy="64" r="3.6" fill="#dc2626"/>
        <circle cx="44" cy="57" r="3.6" fill="#dc2626"/>

        
        <line x1="255" y1="50" x2="238" y2="70" stroke="#94a3b8" stroke-width="1.5"/>
        <line x1="255" y1="50" x2="272" y2="70" stroke="#94a3b8" stroke-width="1.5"/>
        <path d="M 230 70 Q 255 76 280 70" fill="none" stroke="#475569" stroke-width="3" stroke-linecap="round"/>

        
        
        <circle cx="238" cy="64" r="3.6" fill="#dc2626"/>
        <circle cx="246" cy="64" r="3.6" fill="#dc2626"/>
        <circle cx="242" cy="57" r="3.6" fill="#dc2626"/>
        <circle cx="250" cy="57" r="3.6" fill="#dc2626"/>
        
        <circle cx="262" cy="64" r="3.6" fill="#ef4444"/>
        <circle cx="270" cy="64" r="3.6" fill="#ef4444"/>
      </svg>
    </div>

    
    <div class="caption">
      Both equations are true because both sides equal 6!
    </div>
  </div>

</body>
</html>

Understanding the Equal Sign Means Same Value

<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <meta name="aspect-ratio" content="4:3">
  <style>
    * {
      box-sizing: border-box;
      margin: 0;
      padding: 0;
      font-family: system-ui, -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
    }

    body {
      width: 100%;
      background: transparent;
      color: #1e2945;
      display: flex;
      flex-direction: column;
      align-items: center;
      justify-content: flex-start;
      padding: 8px 12px;
      user-select: none;
    }

    .main-container {
      width: 100%;
      max-width: 480px;
      display: flex;
      flex-direction: column;
      align-items: center;
      gap: 8px;
    }

    /* Equation Header */
    .equation-row {
      display: flex;
      align-items: center;
      justify-content: center;
      gap: 10px;
      font-size: 20px;
      font-weight: 700;
      width: 100%;
    }

    .pill {
      padding: 5px 14px;
      border-radius: 999px;
      border: 2px solid;
      display: inline-flex;
      align-items: center;
      justify-content: center;
      font-weight: 800;
      letter-spacing: 0.5px;
    }

    .pill-blue {
      background-color: #eff6ff;
      border-color: #3b82f6;
      color: #1d4ed8;
    }

    .pill-orange {
      background-color: #fff7ed;
      border-color: #f97316;
      color: #c2410c;
    }

    .equal-sign {
      color: #64748b;
      font-size: 24px;
      font-weight: 900;
    }

    /* Decomposition Area */
    .decomp-grid {
      display: grid;
      grid-template-columns: 1fr auto 1fr;
      width: 100%;
      align-items: center;
      gap: 6px;
    }

    .decomp-card {
      display: flex;
      flex-direction: column;
      align-items: center;
      background: #f8fafc;
      border: 1.5px solid #e2e8f0;
      border-radius: 12px;
      padding: 6px 4px;
      gap: 4px;
    }

    .decomp-label {
      font-size: 13px;
      font-weight: 700;
      color: #475569;
    }

    .token-group {
      display: flex;
      align-items: center;
      justify-content: center;
      gap: 3px;
    }

    .token-subgroup {
      display: flex;
      gap: 2px;
    }

    .plus-mini {
      font-size: 11px;
      font-weight: 800;
      color: #94a3b8;
      margin: 0 1px;
    }

    .token {
      width: 15px;
      height: 15px;
      border-radius: 50%;
      cursor: pointer;
      box-shadow: inset 0 1px 2px rgba(255,255,255,0.4), 0 1px 2px rgba(0,0,0,0.1);
      transition: outline 0.2s ease, opacity 0.2s ease;
      outline: 2px solid transparent;
    }

    .token.token-blue {
      background-color: #2563eb;
    }

    .token.token-orange {
      background-color: #ea580c;
    }

    .token.highlighted {
      outline: 2.5px solid #fbbf24;
      opacity: 1;
    }

    .arrow-divider {
      color: #94a3b8;
      font-size: 16px;
      font-weight: 800;
    }

    /* SVG Balance Area */
    .scale-wrapper {
      width: 100%;
      position: relative;
      display: flex;
      justify-content: center;
    }

    svg.scale-svg {
      width: 100%;
      max-width: 440px;
      height: auto;
      overflow: visible;
    }

    /* Verification Badge */
    .badge-wrap {
      display: flex;
      justify-content: center;
      width: 100%;
      margin-top: -2px;
    }

    .status-badge {
      background-color: #16a34a;
      color: #ffffff;
      padding: 4px 14px;
      border-radius: 999px;
      font-size: 12px;
      font-weight: 700;
      display: inline-flex;
      align-items: center;
      gap: 5px;
      box-shadow: 0 1px 3px rgba(22, 163, 74, 0.25);
    }

    /* Interactive hint */
    .hint-text {
      font-size: 11px;
      color: #64748b;
      font-weight: 600;
      text-align: center;
    }

    .btn-toggle {
      background: #f1f5f9;
      border: 1px solid #cbd5e1;
      border-radius: 6px;
      color: #334155;
      font-size: 11px;
      font-weight: 700;
      padding: 4px 10px;
      cursor: pointer;
      transition: background-color 0.15s ease;
    }

    .btn-toggle:hover {
      background: #e2e8f0;
    }
  </style>
</head>
<body>

  <div class="main-container">
    
    <div class="equation-row">
      <div class="pill pill-blue">4 + 1</div>
      <div class="equal-sign">=</div>
      <div class="pill pill-orange">2 + 3</div>
    </div>

    
    <div class="decomp-grid">
      
      <div class="decomp-card">
        <div class="token-group">
          <div class="token-subgroup">
            <div class="token token-blue" data-index="0"></div>
            <div class="token token-blue" data-index="1"></div>
            <div class="token token-blue" data-index="2"></div>
            <div class="token token-blue" data-index="3"></div>
          </div>
          <span class="plus-mini">+</span>
          <div class="token-subgroup">
            <div class="token token-blue" data-index="4"></div>
          </div>
        </div>
        <div class="decomp-label">4 + 1 = 5</div>
      </div>

      <div class="arrow-divider">=</div>

      
      <div class="decomp-card">
        <div class="token-group">
          <div class="token-subgroup">
            <div class="token token-orange" data-index="0"></div>
            <div class="token token-orange" data-index="1"></div>
          </div>
          <span class="plus-mini">+</span>
          <div class="token-subgroup">
            <div class="token token-orange" data-index="2"></div>
            <div class="token token-orange" data-index="3"></div>
            <div class="token token-orange" data-index="4"></div>
          </div>
        </div>
        <div class="decomp-label">2 + 3 = 5</div>
      </div>
    </div>

    
    <div class="scale-wrapper">
      <svg class="scale-svg" viewBox="0 0 400 130">
        
        <line x1="200" y1="28" x2="200" y2="108" stroke="#334155" stroke-width="4" stroke-linecap="round"/>
        <polygon points="200,32 176,110 224,110" fill="#475569"/>
        <polygon points="200,32 188,110 212,110" fill="#334155"/>
        <rect x="155" y="110" width="90" height="8" rx="4" fill="#1e293b"/>
        
        
        <circle cx="200" cy="28" r="5" fill="#0f172a"/>
        <circle cx="200" cy="28" r="2.5" fill="#94a3b8"/>

        
        <line x1="60" y1="28" x2="340" y2="28" stroke="#334155" stroke-width="5" stroke-linecap="round"/>
        
        
        <line x1="60" y1="28" x2="30" y2="82" stroke="#64748b" stroke-width="1.5"/>
        <line x1="60" y1="28" x2="90" y2="82" stroke="#64748b" stroke-width="1.5"/>
        <path d="M 22 82 Q 60 92 98 82 Z" fill="#94a3b8"/>
        
        
        <rect x="42" y="52" width="36" height="30" rx="4" fill="#2563eb" stroke="#1d4ed8" stroke-width="1.5"/>
        <text x="60" y="73" fill="#ffffff" font-size="16" font-weight="900" text-anchor="middle">5</text>

        
        <line x1="340" y1="28" x2="310" y2="82" stroke="#64748b" stroke-width="1.5"/>
        <line x1="340" y1="28" x2="370" y2="82" stroke="#64748b" stroke-width="1.5"/>
        <path d="M 302 82 Q 340 92 378 82 Z" fill="#94a3b8"/>

        
        <rect x="322" y="52" width="36" height="30" rx="4" fill="#ea580c" stroke="#c2410c" stroke-width="1.5"/>
        <text x="340" y="73" fill="#ffffff" font-size="16" font-weight="900" text-anchor="middle">5</text>
      </svg>
    </div>

    
    <div class="badge-wrap">
      <div class="status-badge">
        <span>✓</span> Both sides equal 5 — Balanced!
      </div>
    </div>

    
    <div style="display: flex; align-items: center; gap: 8px;">
      <span class="hint-text">Tap dots to match pairs:</span>
      <button class="btn-toggle" id="matchAllBtn">Match All (1-to-1)</button>
    </div>
  </div>

  <script>
    const tokens = document.querySelectorAll('.token');
    const matchBtn = document.getElementById('matchAllBtn');
    let matched = false;

    function highlightPair(index) {
      tokens.forEach(t => {
        if (t.dataset.index === String(index)) {
          t.classList.toggle('highlighted');
        }
      });
    }

    tokens.forEach(token => {
      token.addEventListener('click', () => {
        highlightPair(token.dataset.index);
      });
    });

    matchBtn.addEventListener('click', () => {
      matched = !matched;
      tokens.forEach(t => {
        if (matched) {
          t.classList.add('highlighted');
        } else {
          t.classList.remove('highlighted');
        }
      });
      matchBtn.textContent = matched ? 'Clear Pairs' : 'Match All (1-to-1)';
    });
  </script>
</body>
</html>

<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <meta name="aspect-ratio" content="4:3">
  <style>
    * {
      box-sizing: border-box;
      margin: 0;
      padding: 0;
    }

    body {
      font-family: system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
      background: #ffffff;
      color: #1e2945;
      display: flex;
      flex-direction: column;
      align-items: center;
      justify-content: space-between;
      min-height: 100%;
      padding: 12px 10px;
      overflow-x: hidden;
    }

    .diagram-area {
      width: 100%;
      max-width: 500px;
      display: flex;
      flex-direction: column;
      align-items: center;
      gap: 10px;
    }

    /* Top Expressions and Stars */
    .sides-container {
      display: flex;
      align-items: stretch;
      justify-content: center;
      width: 100%;
      gap: 8px;
    }

    .side-col {
      flex: 1;
      display: flex;
      flex-direction: column;
      align-items: center;
      gap: 6px;
      padding: 10px 8px;
      border-radius: 12px;
      transition: all 0.3s ease;
    }

    .left-side {
      background: #fff7ed;
      border: 2px solid #fed7aa;
    }

    .right-side {
      background: #faf5ff;
      border: 2px solid #e9d5ff;
    }

    .expr-label {
      font-size: 20px;
      font-weight: 800;
      letter-spacing: -0.5px;
    }

    .left-side .expr-label {
      color: #ea580c;
    }

    .right-side .expr-label {
      color: #9333ea;
    }

    .star-groups {
      display: flex;
      align-items: center;
      justify-content: center;
      gap: 4px;
      flex-wrap: wrap;
    }

    .star-cluster {
      display: flex;
      gap: 3px;
      align-items: center;
      background: rgba(255, 255, 255, 0.7);
      padding: 4px 6px;
      border-radius: 8px;
    }

    .star-svg {
      width: 17px;
      height: 17px;
      display: block;
    }

    .left-star {
      fill: #f97316;
    }

    .right-star {
      fill: #a855f7;
    }

    .plus-sign {
      font-size: 14px;
      font-weight: 800;
      color: #94a3b8;
    }

    /* Center Bridge */
    .center-equals-col {
      display: flex;
      flex-direction: column;
      align-items: center;
      justify-content: center;
      width: 32px;
      flex-shrink: 0;
    }

    .center-eq-top {
      font-size: 24px;
      font-weight: 800;
      color: #94a3b8;
    }

    /* Down Arrows */
    .arrows-row {
      display: flex;
      align-items: center;
      justify-content: center;
      width: 100%;
      gap: 8px;
    }

    .arrow-box {
      flex: 1;
      display: flex;
      justify-content: center;
      align-items: center;
      transition: opacity 0.3s ease, transform 0.3s ease;
    }

    .arrow-svg {
      width: 24px;
      height: 24px;
      stroke-width: 3;
      fill: none;
      stroke-linecap: round;
      stroke-linejoin: round;
    }

    .arrow-left {
      stroke: #ea580c;
    }

    .arrow-right {
      stroke: #9333ea;
    }

    /* Evaluated Row */
    .eval-row {
      display: flex;
      align-items: center;
      justify-content: center;
      width: 100%;
      gap: 8px;
    }

    .eval-box {
      flex: 1;
      text-align: center;
      padding: 10px 0;
      border-radius: 12px;
      font-size: 26px;
      font-weight: 900;
      transition: all 0.3s ease;
    }

    .eval-left {
      background: #ea580c;
      color: #ffffff;
      box-shadow: 0 4px 10px rgba(234, 88, 12, 0.2);
    }

    .eval-right {
      background: #9333ea;
      color: #ffffff;
      box-shadow: 0 4px 10px rgba(147, 51, 234, 0.2);
    }

    .big-eq {
      width: 32px;
      flex-shrink: 0;
      text-align: center;
      font-size: 32px;
      font-weight: 900;
      color: #0f172a;
      transition: transform 0.3s ease, color 0.3s ease;
    }

    /* True Banner */
    .banner-container {
      width: 100%;
      height: 46px;
      position: relative;
      display: flex;
      align-items: center;
      justify-content: center;
    }

    .result-banner {
      background: #ecfdf5;
      border: 2px solid #10b981;
      color: #047857;
      padding: 8px 24px;
      border-radius: 999px;
      font-size: 17px;
      font-weight: 800;
      display: flex;
      align-items: center;
      gap: 6px;
      box-shadow: 0 2px 8px rgba(16, 185, 129, 0.15);
      transition: all 0.3s ease;
    }

    /* Stepper Controls */
    .controls {
      display: flex;
      align-items: center;
      justify-content: center;
      gap: 8px;
      margin-top: 8px;
      width: 100%;
    }

    .btn-step {
      background: #f1f5f9;
      border: 1px solid #cbd5e1;
      border-radius: 8px;
      padding: 6px 12px;
      font-size: 14px;
      font-weight: 600;
      color: #334155;
      cursor: pointer;
      display: flex;
      align-items: center;
      gap: 4px;
    }

    .btn-step:active {
      background: #e2e8f0;
    }

    .step-pills {
      display: flex;
      gap: 6px;
    }

    .pill {
      border: none;
      padding: 6px 12px;
      border-radius: 999px;
      font-size: 13px;
      font-weight: 700;
      cursor: pointer;
      background: #f1f5f9;
      color: #64748b;
      transition: all 0.2s ease;
    }

    .pill.active {
      background: #22b7ff;
      color: #ffffff;
    }

    /* Step Visibility States */
    .step-dimmed {
      opacity: 0.15 !important;
      transform: scale(0.95);
    }

    .step-hidden {
      opacity: 0 !important;
      visibility: hidden;
      transform: translateY(-6px);
    }
  </style>
</head>
<body>

  <div class="diagram-area">
    
    <div class="sides-container">
      
      <div class="side-col left-side" id="leftExpr">
        <div class="expr-label">3 + 3</div>
        <div class="star-groups">
          <div class="star-cluster">
            <svg class="star-svg left-star" viewBox="0 0 24 24"><polygon points="12,2 15,9 22,9 16.5,14 18.5,21 12,17 5.5,21 7.5,14 2,9 9,9"/></svg>
            <svg class="star-svg left-star" viewBox="0 0 24 24"><polygon points="12,2 15,9 22,9 16.5,14 18.5,21 12,17 5.5,21 7.5,14 2,9 9,9"/></svg>
            <svg class="star-svg left-star" viewBox="0 0 24 24"><polygon points="12,2 15,9 22,9 16.5,14 18.5,21 12,17 5.5,21 7.5,14 2,9 9,9"/></svg>
          </div>
          <span class="plus-sign">+</span>
          <div class="star-cluster">
            <svg class="star-svg left-star" viewBox="0 0 24 24"><polygon points="12,2 15,9 22,9 16.5,14 18.5,21 12,17 5.5,21 7.5,14 2,9 9,9"/></svg>
            <svg class="star-svg left-star" viewBox="0 0 24 24"><polygon points="12,2 15,9 22,9 16.5,14 18.5,21 12,17 5.5,21 7.5,14 2,9 9,9"/></svg>
            <svg class="star-svg left-star" viewBox="0 0 24 24"><polygon points="12,2 15,9 22,9 16.5,14 18.5,21 12,17 5.5,21 7.5,14 2,9 9,9"/></svg>
          </div>
        </div>
      </div>

      <div class="center-equals-col">
        <span class="center-eq-top">=</span>
      </div>

      
      <div class="side-col right-side" id="rightExpr">
        <div class="expr-label">4 + 2</div>
        <div class="star-groups">
          <div class="star-cluster">
            <svg class="star-svg right-star" viewBox="0 0 24 24"><polygon points="12,2 15,9 22,9 16.5,14 18.5,21 12,17 5.5,21 7.5,14 2,9 9,9"/></svg>
            <svg class="star-svg right-star" viewBox="0 0 24 24"><polygon points="12,2 15,9 22,9 16.5,14 18.5,21 12,17 5.5,21 7.5,14 2,9 9,9"/></svg>
            <svg class="star-svg right-star" viewBox="0 0 24 24"><polygon points="12,2 15,9 22,9 16.5,14 18.5,21 12,17 5.5,21 7.5,14 2,9 9,9"/></svg>
            <svg class="star-svg right-star" viewBox="0 0 24 24"><polygon points="12,2 15,9 22,9 16.5,14 18.5,21 12,17 5.5,21 7.5,14 2,9 9,9"/></svg>
          </div>
          <span class="plus-sign">+</span>
          <div class="star-cluster">
            <svg class="star-svg right-star" viewBox="0 0 24 24"><polygon points="12,2 15,9 22,9 16.5,14 18.5,21 12,17 5.5,21 7.5,14 2,9 9,9"/></svg>
            <svg class="star-svg right-star" viewBox="0 0 24 24"><polygon points="12,2 15,9 22,9 16.5,14 18.5,21 12,17 5.5,21 7.5,14 2,9 9,9"/></svg>
          </div>
        </div>
      </div>
    </div>

    
    <div class="arrows-row">
      <div class="arrow-box" id="leftArrow">
        <svg class="arrow-svg arrow-left" viewBox="0 0 24 24"><line x1="12" y1="3" x2="12" y2="21"/><polyline points="6,15 12,21 18,15"/></svg>
      </div>
      <div class="center-equals-col"></div>
      <div class="arrow-box" id="rightArrow">
        <svg class="arrow-svg arrow-right" viewBox="0 0 24 24"><line x1="12" y1="3" x2="12" y2="21"/><polyline points="6,15 12,21 18,15"/></svg>
      </div>
    </div>

    
    <div class="eval-row">
      <div class="eval-box eval-left" id="boxLeft">6</div>
      <div class="big-eq" id="centerEq">=</div>
      <div class="eval-box eval-right" id="boxRight">6</div>
    </div>

    
    <div class="banner-container">
      <div class="result-banner" id="banner">
        <span>6 = 6 (True!)</span>
      </div>
    </div>
  </div>

  
  <div class="controls">
    <button class="btn-step" id="playBtn" aria-label="Play or Pause">
      <span id="playIcon">⏸</span>
    </button>
    <div class="step-pills">
      <button class="pill active" id="pill0">1. Stars</button>
      <button class="pill" id="pill1">2. Add</button>
      <button class="pill" id="pill2">3. Balance</button>
    </div>
  </div>

  <script>
    const leftArrow = document.getElementById('leftArrow');
    const rightArrow = document.getElementById('rightArrow');
    const boxLeft = document.getElementById('boxLeft');
    const boxRight = document.getElementById('boxRight');
    const centerEq = document.getElementById('centerEq');
    const banner = document.getElementById('banner');
    const pills = [document.getElementById('pill0'), document.getElementById('pill1'), document.getElementById('pill2')];
    const playBtn = document.getElementById('playBtn');
    const playIcon = document.getElementById('playIcon');

    let currentStep = 0;
    let playing = true;
    let timer = null;

    function renderStep(step) {
      currentStep = step;
      pills.forEach((p, idx) => p.classList.toggle('active', idx === step));

      if (step === 0) {
        leftArrow.classList.add('step-dimmed');
        rightArrow.classList.add('step-dimmed');
        boxLeft.classList.add('step-dimmed');
        boxRight.classList.add('step-dimmed');
        centerEq.classList.add('step-dimmed');
        banner.classList.add('step-hidden');
      } else if (step === 1) {
        leftArrow.classList.remove('step-dimmed');
        rightArrow.classList.remove('step-dimmed');
        boxLeft.classList.remove('step-dimmed');
        boxRight.classList.remove('step-dimmed');
        centerEq.classList.remove('step-dimmed');
        banner.classList.add('step-hidden');
      } else {
        leftArrow.classList.remove('step-dimmed');
        rightArrow.classList.remove('step-dimmed');
        boxLeft.classList.remove('step-dimmed');
        boxRight.classList.remove('step-dimmed');
        centerEq.classList.remove('step-dimmed');
        banner.classList.remove('step-hidden');
      }
    }

    function nextStep() {
      renderStep((currentStep + 1) % 3);
    }

    function startAutoPlay() {
      if (timer) clearInterval(timer);
      timer = setInterval(nextStep, 3200);
      playing = true;
      playIcon.textContent = '⏸';
    }

    function pauseAutoPlay() {
      if (timer) clearInterval(timer);
      timer = null;
      playing = false;
      playIcon.textContent = '▶';
    }

    playBtn.addEventListener('click', () => {
      if (playing) pauseAutoPlay();
      else {
        nextStep();
        startAutoPlay();
      }
    });

    pills.forEach((p, idx) => {
      p.addEventListener('click', () => {
        pauseAutoPlay();
        renderStep(idx);
      });
    });

    // Start on step 0
    renderStep(0);
    startAutoPlay();
  </script>
</body>
</html>

<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <meta name="aspect-ratio" content="4:3">
  <style>
    * {
      box-sizing: border-box;
      margin: 0;
      padding: 0;
    }
    body {
      width: 100%;
      min-height: 100%;
      background: #f8f9fa;
      font-family: system-ui, -apple-system, sans-serif;
      color: #1e2945;
      display: flex;
      flex-direction: column;
      align-items: center;
      justify-content: center;
      padding: 12px;
      user-select: none;
    }
    .scale-wrap {
      width: 100%;
      max-width: 560px;
      position: relative;
    }
    svg {
      width: 100%;
      height: auto;
      display: block;
      overflow: visible;
    }

    /* Bobbing & Settling Animation */
    .animated-rig {
      transform-origin: 300px 150px;
      animation: settleScale 4.5s ease-out forwards;
    }
    .pan-counter-left {
      transform-origin: 100px 150px;
      animation: counterRotateLeft 4.5s ease-out forwards;
    }
    .pan-counter-right {
      transform-origin: 500px 150px;
      animation: counterRotateRight 4.5s ease-out forwards;
    }

    @keyframes settleScale {
      0%   { transform: rotate(-5deg); }
      20%  { transform: rotate(4deg); }
      40%  { transform: rotate(-2.5deg); }
      60%  { transform: rotate(1.5deg); }
      80%  { transform: rotate(-0.5deg); }
      100% { transform: rotate(0deg); }
    }
    @keyframes counterRotateLeft {
      0%   { transform: rotate(5deg); }
      20%  { transform: rotate(-4deg); }
      40%  { transform: rotate(2.5deg); }
      60%  { transform: rotate(-1.5deg); }
      80%  { transform: rotate(0.5deg); }
      100% { transform: rotate(0deg); }
    }
    @keyframes counterRotateRight {
      0%   { transform: rotate(5deg); }
      20%  { transform: rotate(-4deg); }
      40%  { transform: rotate(2.5deg); }
      60%  { transform: rotate(-1.5deg); }
      80%  { transform: rotate(0.5deg); }
      100% { transform: rotate(0deg); }
    }

    /* Fulcrum Glowing Equal Sign */
    .equal-glow {
      filter: drop-shadow(0 0 8px rgba(34, 183, 255, 0.7));
      animation: pulseGlow 2.5s ease-in-out infinite alternate;
    }
    @keyframes pulseGlow {
      0% {
        filter: drop-shadow(0 0 4px rgba(34, 183, 255, 0.4));
      }
      100% {
        filter: drop-shadow(0 0 12px rgba(34, 183, 255, 0.9));
      }
    }

    /* Controls */
    .controls {
      display: flex;
      justify-content: center;
      margin-top: 4px;
    }
    .rebalance-btn {
      background: #ffffff;
      border: 1px solid #e6e6e6;
      color: #1e2945;
      font-size: 14px;
      font-weight: 600;
      padding: 6px 16px;
      border-radius: 20px;
      cursor: pointer;
      box-shadow: 0 1px 3px rgba(0,0,0,0.05);
      transition: background-color 0.2s, box-shadow 0.2s;
    }
    .rebalance-btn:hover {
      background: #f1f5f9;
      box-shadow: 0 2px 5px rgba(0,0,0,0.1);
    }
  </style>
</head>
<body>

  <div class="scale-wrap">
    <svg id="scaleSvg" viewBox="0 0 600 340" aria-label="Balanced scale showing 3 + 2 = 5">
      <defs>
        
        <g id="red-apple">
          <path d="M0 -12 C-2 -18 6 -20 8 -17 C8 -15 4 -12 1 -11" stroke="#5c3a21" stroke-width="2" fill="none" stroke-linecap="round"/>
          <path d="M1 -15 C6 -18 10 -15 9 -12 C5 -12 2 -14 1 -15" fill="#48bb78"/>
          <circle cx="-6" cy="0" r="10" fill="#e53e3e"/>
          <circle cx="6" cy="0" r="10" fill="#e53e3e"/>
          <ellipse cx="0" cy="5" rx="10" ry="8" fill="#e53e3e"/>
          <ellipse cx="-4" cy="-3" rx="3" ry="5" fill="#feb2b2" opacity="0.6"/>
        </g>
        <g id="green-apple">
          <path d="M0 -12 C-2 -18 6 -20 8 -17 C8 -15 4 -12 1 -11" stroke="#5c3a21" stroke-width="2" fill="none" stroke-linecap="round"/>
          <path d="M1 -15 C6 -18 10 -15 9 -12 C5 -12 2 -14 1 -15" fill="#2f855a"/>
          <circle cx="-6" cy="0" r="10" fill="#38a169"/>
          <circle cx="6" cy="0" r="10" fill="#38a169"/>
          <ellipse cx="0" cy="5" rx="10" ry="8" fill="#38a169"/>
          <ellipse cx="-4" cy="-3" rx="3" ry="5" fill="#9ae6b4" opacity="0.6"/>
        </g>
        <g id="yellow-apple">
          <path d="M0 -12 C-2 -18 6 -20 8 -17 C8 -15 4 -12 1 -11" stroke="#5c3a21" stroke-width="2" fill="none" stroke-linecap="round"/>
          <path d="M1 -15 C6 -18 10 -15 9 -12 C5 -12 2 -14 1 -15" fill="#48bb78"/>
          <circle cx="-6" cy="0" r="10" fill="#ecc94b"/>
          <circle cx="6" cy="0" r="10" fill="#ecc94b"/>
          <ellipse cx="0" cy="5" rx="10" ry="8" fill="#ecc94b"/>
          <ellipse cx="-4" cy="-3" rx="3" ry="5" fill="#fefcbf" opacity="0.7"/>
        </g>
      </defs>

      
      <polygon points="300,150 260,290 340,290" fill="#cbd5e1"/>
      <polygon points="300,150 300,290 340,290" fill="#94a3b8"/>
      <rect x="230" y="285" width="140" height="14" rx="7" fill="#64748b"/>

      
      <g id="rig" class="animated-rig">
        
        <rect x="90" y="145" width="420" height="10" rx="5" fill="#475569"/>

        
        <g class="pan-counter-left">
          
          <line x1="100" y1="150" x2="40" y2="230" stroke="#94a3b8" stroke-width="2.5"/>
          <line x1="100" y1="150" x2="160" y2="230" stroke="#94a3b8" stroke-width="2.5"/>
          
          
          <path d="M 30,230 Q 100,265 170,230 Z" fill="#e2e8f0" stroke="#cbd5e1" stroke-width="2"/>
          <ellipse cx="100" cy="230" rx="70" ry="8" fill="#f1f5f9" stroke="#cbd5e1" stroke-width="1.5"/>

          
          <use href="#red-apple" x="65" y="215"/>
          <use href="#red-apple" x="88" y="218"/>
          <use href="#red-apple" x="77" y="196"/>

          
          <use href="#green-apple" x="122" y="216"/>
          <use href="#green-apple" x="135" y="198"/>

          
          <rect x="52" y="260" width="96" height="28" rx="14" fill="#ffffff" stroke="#e6e6e6" stroke-width="1.5"/>
          <text x="100" y="279" text-anchor="middle" fill="#1e2945" font-size="16" font-weight="700">3 + 2 = 5</text>
        </g>

        
        <g class="pan-counter-right">
          
          <line x1="500" y1="150" x2="440" y2="230" stroke="#94a3b8" stroke-width="2.5"/>
          <line x1="500" y1="150" x2="560" y2="230" stroke="#94a3b8" stroke-width="2.5"/>

          
          <path d="M 430,230 Q 500,265 570,230 Z" fill="#e2e8f0" stroke="#cbd5e1" stroke-width="2"/>
          <ellipse cx="500" cy="230" rx="70" ry="8" fill="#f1f5f9" stroke="#cbd5e1" stroke-width="1.5"/>

          
          <use href="#yellow-apple" x="462" y="216"/>
          <use href="#yellow-apple" x="485" y="218"/>
          <use href="#yellow-apple" x="510" y="217"/>
          <use href="#yellow-apple" x="532" y="215"/>
          <use href="#yellow-apple" x="498" y="196"/>

          
          <rect x="472" y="260" width="56" height="28" rx="14" fill="#ffffff" stroke="#e6e6e6" stroke-width="1.5"/>
          <text x="500" y="279" text-anchor="middle" fill="#1e2945" font-size="16" font-weight="700">5</text>
        </g>

        
        <circle cx="300" cy="150" r="24" fill="#0284c7" class="equal-glow"/>
        <circle cx="300" cy="150" r="21" fill="#22b7ff"/>
        
        <rect x="288" y="142" width="24" height="5" rx="2.5" fill="#ffffff"/>
        <rect x="288" y="153" width="24" height="5" rx="2.5" fill="#ffffff"/>
      </g>
    </svg>
  </div>

  <div class="controls">
    <button class="rebalance-btn" id="rebalanceBtn" aria-label="Test Balance">⚖️ Test Balance</button>
  </div>

  <script>
    const btn = document.getElementById('rebalanceBtn');
    const rig = document.getElementById('rig');
    const leftPan = document.querySelector('.pan-counter-left');
    const rightPan = document.querySelector('.pan-counter-right');

    btn.addEventListener('click', () => {
      // Re-trigger CSS animation smoothly
      rig.style.animation = 'none';
      leftPan.style.animation = 'none';
      rightPan.style.animation = 'none';

      void rig.offsetWidth; // Force reflow

      rig.style.animation = 'settleScale 4.5s ease-out forwards';
      leftPan.style.animation = 'counterRotateLeft 4.5s ease-out forwards';
      rightPan.style.animation = 'counterRotateRight 4.5s ease-out forwards';
    });
  </script>
</body>
</html>

<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <meta name="aspect-ratio" content="4:3">
  <title>Curved 3D Solid Shapes</title>
  <style>
    * { box-sizing: border-box; margin: 0; padding: 0; }
    body {
      font-family: system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
      color: #1e2945;
      background: transparent;
      padding: 8px;
      user-select: none;
      -webkit-user-select: none;
    }
    .grid {
      display: grid;
      grid-template-columns: repeat(3, 1fr);
      gap: 8px;
      width: 100%;
    }
    .col {
      background: #f8fafc;
      border-radius: 12px;
      padding: 10px 6px;
      display: flex;
      flex-direction: column;
      align-items: center;
      text-align: center;
      cursor: pointer;
      transition: background-color 0.25s ease, box-shadow 0.25s ease;
      box-shadow: 0 0 0 2px transparent;
    }
    .col-sphere { background: #f0f7ff; }
    .col-cylinder { background: #f0fdf4; }
    .col-cone { background: #fff5f5; }

    .col.active.col-sphere {
      box-shadow: 0 0 0 2px #0284c7, 0 4px 12px rgba(2, 132, 199, 0.15);
      background: #e0f2fe;
    }
    .col.active.col-cylinder {
      box-shadow: 0 0 0 2px #16a34a, 0 4px 12px rgba(22, 163, 74, 0.15);
      background: #dcfce7;
    }
    .col.active.col-cone {
      box-shadow: 0 0 0 2px #ea580c, 0 4px 12px rgba(234, 88, 12, 0.15);
      background: #ffedd5;
    }

    .title-badge {
      font-size: 16px;
      font-weight: 800;
      letter-spacing: -0.01em;
      margin-bottom: 2px;
    }
    .col-sphere .title-badge { color: #0369a1; }
    .col-cylinder .title-badge { color: #15803d; }
    .col-cone .title-badge { color: #c2410c; }

    .phonetic {
      font-size: 11px;
      font-weight: 600;
      color: #64748b;
      margin-bottom: 8px;
    }

    .svg-stage {
      width: 100%;
      max-width: 130px;
      height: 110px;
      display: flex;
      align-items: center;
      justify-content: center;
      margin-bottom: 6px;
    }
    .svg-stage svg {
      width: 100%;
      height: 100%;
      overflow: visible;
    }

    .badge-group {
      display: flex;
      flex-direction: column;
      gap: 4px;
      width: 100%;
      margin: 6px 0;
    }
    .badge {
      font-size: 11px;
      font-weight: 700;
      padding: 3px 6px;
      border-radius: 6px;
      background: #ffffff;
      border: 1px solid rgba(0,0,0,0.06);
      display: flex;
      align-items: center;
      justify-content: center;
      gap: 4px;
    }

    .real-items {
      display: flex;
      justify-content: center;
      gap: 8px;
      margin-top: 4px;
      font-size: 20px;
    }
    .real-item-box {
      display: flex;
      flex-direction: column;
      align-items: center;
      gap: 1px;
    }
    .real-item-box span {
      font-size: 9px;
      font-weight: 600;
      color: #64748b;
    }

    /* Highlight ring animations */
    .glow-pulse {
      animation: pulse 1.8s infinite ease-in-out;
    }
    @keyframes pulse {
      0%, 100% { stroke-opacity: 0.9; stroke-width: 2.5; }
      50% { stroke-opacity: 0.3; stroke-width: 1.5; }
    }

    .caption-bar {
      margin-top: 10px;
      background: #ffffff;
      border: 1px solid #e2e8f0;
      border-radius: 10px;
      padding: 8px 12px;
      font-size: 13px;
      font-weight: 600;
      text-align: center;
      color: #1e2945;
      display: flex;
      align-items: center;
      justify-content: center;
      gap: 6px;
      min-height: 40px;
    }
    .caption-accent {
      font-weight: 800;
    }

    @media (max-width: 480px) {
      body { padding: 4px; }
      .grid { gap: 4px; }
      .col { padding: 8px 3px; border-radius: 8px; }
      .title-badge { font-size: 14px; }
      .phonetic { font-size: 10px; }
      .svg-stage { height: 95px; }
      .badge { font-size: 10px; padding: 2px 4px; }
      .real-items { font-size: 16px; gap: 4px; }
      .caption-bar { font-size: 12px; padding: 6px 8px; }
    }
  </style>
</head>
<body>

  <div class="grid">
    
    <div class="col col-sphere active" id="sphereCol" onclick="selectShape('sphere')">
      <div class="title-badge">Sphere</div>
      <div class="phonetic">"sfeer"</div>
      
      <div class="svg-stage">
        <svg viewBox="0 0 120 110">
          <defs>
            <radialGradient id="sphereGrad" cx="38%" cy="32%" r="65%">
              <stop offset="0%" stop-color="#7dd3fc" />
              <stop offset="45%" stop-color="#0284c7" />
              <stop offset="100%" stop-color="#075985" />
            </radialGradient>
          </defs>
          
          <circle cx="60" cy="55" r="42" fill="url(#sphereGrad)" filter="drop-shadow(0 4px 6px rgba(0,0,0,0.15))" />
          
          <ellipse cx="60" cy="55" rx="42" ry="12" fill="none" stroke="#bae6fd" stroke-width="1.5" stroke-dasharray="3,3" opacity="0.6" />
          
          <path d="M 32 30 A 35 35 0 0 1 70 20" stroke="#ffffff" stroke-width="2.5" stroke-linecap="round" fill="none" opacity="0.8" />
        </svg>
      </div>

      <div class="badge-group">
        <div class="badge">⚪ 0 Flat Faces</div>
        <div class="badge">🔄 Curved All Around</div>
        <div class="badge" style="color:#0369a1;">⚽ Rolls smoothly</div>
      </div>

      <div class="real-items">
        <div class="real-item-box">🏀<span>Basketball</span></div>
        <div class="real-item-box">🍊<span>Orange</span></div>
      </div>
    </div>

    
    <div class="col col-cylinder" id="cylinderCol" onclick="selectShape('cylinder')">
      <div class="title-badge">Cylinder</div>
      <div class="phonetic">"sil-in-der"</div>

      <div class="svg-stage">
        <svg viewBox="0 0 120 110">
          <defs>
            <linearGradient id="cylGrad" x1="0%" y1="0%" x2="100%" y2="0%">
              <stop offset="0%" stop-color="#15803d" />
              <stop offset="30%" stop-color="#22c55e" />
              <stop offset="70%" stop-color="#4ade80" />
              <stop offset="100%" stop-color="#166534" />
            </linearGradient>
            <linearGradient id="topBaseGrad" x1="0%" y1="0%" x2="0%" y2="100%">
              <stop offset="0%" stop-color="#bbf7d0" />
              <stop offset="100%" stop-color="#86efac" />
            </linearGradient>
          </defs>
          
          <ellipse cx="60" cy="94" rx="36" ry="9" fill="rgba(0,0,0,0.12)" />
          
          <path d="M 28 32 L 28 84 A 32 10 0 0 0 92 84 L 92 32 Z" fill="url(#cylGrad)" />
          
          <ellipse cx="60" cy="84" rx="32" ry="10" fill="#16a34a" />
          <ellipse cx="60" cy="84" rx="32" ry="10" fill="none" stroke="#22c55e" stroke-width="1.5" stroke-dasharray="3,3" />
          
          <ellipse cx="60" cy="32" rx="32" ry="10" fill="url(#topBaseGrad)" stroke="#15803d" stroke-width="1.5" class="cyl-top" />
          
          <circle cx="60" cy="32" r="3" fill="#15803d" />
        </svg>
      </div>

      <div class="badge-group">
        <div class="badge">⭕ 2 Flat Circles</div>
        <div class="badge">🌯 1 Curved Body</div>
        <div class="badge" style="color:#15803d;">🔄 Rolls &amp; Slides</div>
      </div>

      <div class="real-items">
        <div class="real-item-box">🥫<span>Soup Can</span></div>
        <div class="real-item-box">🥁<span>Drum</span></div>
      </div>
    </div>

    
    <div class="col col-cone" id="coneCol" onclick="selectShape('cone')">
      <div class="title-badge">Cone</div>
      <div class="phonetic">"kohn"</div>

      <div class="svg-stage">
        <svg viewBox="0 0 120 110">
          <defs>
            <linearGradient id="coneGrad" x1="0%" y1="0%" x2="100%" y2="0%">
              <stop offset="0%" stop-color="#c2410c" />
              <stop offset="40%" stop-color="#f97316" />
              <stop offset="80%" stop-color="#fb923c" />
              <stop offset="100%" stop-color="#9a3412" />
            </linearGradient>
            <linearGradient id="coneBaseGrad" x1="0%" y1="0%" x2="0%" y2="100%">
              <stop offset="0%" stop-color="#fed7aa" />
              <stop offset="100%" stop-color="#fdba74" />
            </linearGradient>
          </defs>
          
          <ellipse cx="60" cy="94" rx="36" ry="9" fill="rgba(0,0,0,0.12)" />
          
          <path d="M 60 16 L 26 84 A 34 11 0 0 0 94 84 Z" fill="url(#coneGrad)" />
          
          <ellipse cx="60" cy="84" rx="34" ry="11" fill="none" stroke="#fed7aa" stroke-width="1.5" stroke-dasharray="3,3" />
          
          <circle cx="60" cy="16" r="4" fill="#c2410c" stroke="#ffffff" stroke-width="1.5" class="glow-pulse" />
        </svg>
      </div>

      <div class="badge-group">
        <div class="badge">⭕ 1 Flat Circle Base</div>
        <div class="badge">🔺 1 Pointy Apex</div>
        <div class="badge" style="color:#c2410c;">💫 Rolls in Circle</div>
      </div>

      <div class="real-items">
        <div class="real-item-box">🎉<span>Party Hat</span></div>
        <div class="real-item-box">🍦<span>Ice Cream</span></div>
      </div>
    </div>
  </div>

  
  <div class="caption-bar" id="captionBar">
    <span id="captionIcon">🏀</span>
    <span id="captionText"><strong class="caption-accent" style="color:#0369a1;">Sphere:</strong> Completely curved with no flat sides. Rolls in any direction!</span>
  </div>

  <script>
    const data = {
      sphere: {
        icon: '🏀',
        color: '#0369a1',
        name: 'Sphere',
        text: 'Completely curved with 0 flat faces. It can roll in all directions!'
      },
      cylinder: {
        icon: '🥫',
        color: '#15803d',
        name: 'Cylinder',
        text: '2 flat circular faces on top and bottom. Rolls on its curved side, slides on its flat faces!'
      },
      cone: {
        icon: '🎉',
        color: '#c2410c',
        name: 'Cone',
        text: '1 flat circular face at the base and 1 pointy vertex at top. Rolls around in a circle!'
      }
    };

    function selectShape(shape) {
      document.getElementById('sphereCol').classList.toggle('active', shape === 'sphere');
      document.getElementById('cylinderCol').classList.toggle('active', shape === 'cylinder');
      document.getElementById('coneCol').classList.toggle('active', shape === 'cone');

      const info = data[shape];
      const icon = document.getElementById('captionIcon');
      const text = document.getElementById('captionText');

      icon.textContent = info.icon;
      text.innerHTML = `<strong class="caption-accent" style="color:${info.color};">${info.name}:</strong> ${info.text}`;
    }
  </script>
</body>
</html>

Naming and Describing Solid Shapes

<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <meta name="aspect-ratio" content="4:3">
  <style>
    * {
      box-sizing: border-box;
      margin: 0;
      padding: 0;
      user-select: none;
      -webkit-user-select: none;
    }

    body {
      font-family: system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
      background: #f8fafc;
      color: #1e2945;
      padding: 10px;
      display: flex;
      flex-direction: column;
      align-items: center;
      justify-content: space-between;
      min-height: 100%;
    }

    /* Interactive mode selector */
    .toolbar {
      display: flex;
      gap: 6px;
      margin-bottom: 8px;
      width: 100%;
      max-width: 580px;
      justify-content: center;
    }

    .tool-btn {
      flex: 1;
      max-width: 110px;
      padding: 6px 4px;
      border: 1px solid #cbd5e1;
      background: #ffffff;
      border-radius: 8px;
      font-size: 12px;
      font-weight: 700;
      color: #475569;
      cursor: pointer;
      display: flex;
      align-items: center;
      justify-content: center;
      gap: 4px;
      box-shadow: 0 1px 2px rgba(0,0,0,0.04);
      transition: background 0.2s, border-color 0.2s, color 0.2s, box-shadow 0.2s;
    }

    .tool-btn.active {
      background: #0284c7;
      color: #ffffff;
      border-color: #0284c7;
      box-shadow: 0 2px 6px rgba(2,132,199,0.25);
    }

    /* 3 Columns Grid */
    .grid {
      display: grid;
      grid-template-columns: repeat(3, 1fr);
      gap: 8px;
      width: 100%;
      max-width: 580px;
      flex: 1;
    }

    .prism-card {
      background: #ffffff;
      border: 1px solid #e2e8f0;
      border-radius: 12px;
      padding: 8px 6px;
      display: flex;
      flex-direction: column;
      align-items: center;
      justify-content: space-between;
      text-align: center;
      position: relative;
      overflow: hidden;
      box-shadow: 0 2px 6px rgba(0,0,0,0.03);
    }

    /* Real-world badge */
    .meta-tag {
      font-size: 11px;
      font-weight: 700;
      padding: 2px 8px;
      border-radius: 12px;
      display: inline-flex;
      align-items: center;
      gap: 4px;
      margin-bottom: 4px;
    }

    .tag-cube { background: #fee2e2; color: #b91c1c; }
    .tag-rect { background: #e0f2fe; color: #0369a1; }
    .tag-tri  { background: #dcfce7; color: #15803d; }

    /* SVG container */
    .svg-wrap {
      width: 100%;
      max-width: 140px;
      height: 120px;
      display: flex;
      align-items: center;
      justify-content: center;
      margin: 2px 0;
    }

    svg {
      width: 100%;
      height: 100%;
      overflow: visible;
    }

    /* Title */
    .prism-title {
      font-size: 13px;
      font-weight: 800;
      color: #0f172a;
      line-height: 1.15;
      margin-bottom: 6px;
    }

    /* Stats Chips */
    .stats-list {
      display: flex;
      flex-direction: column;
      gap: 3px;
      width: 100%;
    }

    .stat-chip {
      font-size: 11px;
      font-weight: 600;
      padding: 3px 4px;
      border-radius: 6px;
      background: #f1f5f9;
      color: #334155;
      display: flex;
      align-items: center;
      justify-content: center;
      gap: 3px;
      transition: background 0.2s, color 0.2s;
    }

    .stat-chip.hl-face   { background: #ffedd5; color: #c2410c; font-weight: 700; }
    .stat-chip.hl-vertex { background: #fef08a; color: #854d0e; font-weight: 700; }
    .stat-chip.hl-edge   { background: #dbeafe; color: #1d4ed8; font-weight: 700; }

    /* SVG Highlight styling */
    .edge-line {
      stroke-linecap: round;
      stroke-linejoin: round;
      transition: stroke 0.2s, stroke-width 0.2s;
    }

    .face-poly {
      transition: fill 0.2s, stroke 0.2s, opacity 0.2s;
    }

    .vertex-dot {
      transition: transform 0.2s, r 0.2s, fill 0.2s;
    }

    .mode-vertices .vertex-dot {
      fill: #eab308 !important;
      stroke: #713f12 !important;
      stroke-width: 1.5px !important;
      r: 4.5px !important;
    }

    .mode-edges .edge-line {
      stroke: #2563eb !important;
      stroke-width: 3.5px !important;
    }

    .mode-faces .face-poly {
      stroke: #ea580c !important;
      stroke-width: 2px !important;
    }

    @media (max-width: 380px) {
      .prism-title { font-size: 11px; }
      .stat-chip { font-size: 10px; padding: 2px; }
      .tool-btn { font-size: 11px; padding: 4px 2px; }
      .meta-tag { font-size: 10px; }
    }
  </style>
</head>
<body>

  
  <div class="toolbar">
    <button class="tool-btn active" data-mode="all">✨ All</button>
    <button class="tool-btn" data-mode="faces">🔲 Faces</button>
    <button class="tool-btn" data-mode="vertices">● Vertices</button>
    <button class="tool-btn" data-mode="edges">━ Edges</button>
  </div>

  
  <div class="grid" id="prismsGrid">

    
    <div class="prism-card" style="border-top: 3px solid #f87171;">
      <span class="meta-tag tag-cube">🎲 Dice</span>

      <div class="svg-wrap">
        <svg viewBox="0 0 140 120">
          
          <line class="edge-line" x1="40" y1="90" x2="40" y2="40" stroke="#fca5a5" stroke-dasharray="3,3" stroke-width="1.5"/>
          <line class="edge-line" x1="40" y1="40" x2="70" y2="15" stroke="#fca5a5" stroke-dasharray="3,3" stroke-width="1.5"/>
          <line class="edge-line" x1="40" y1="90" x2="100" y2="90" stroke="#fca5a5" stroke-dasharray="3,3" stroke-width="1.5"/>

          
          <polygon class="face-poly" points="70,15 100,40 70,65 40,40" fill="#fecaca" stroke="#dc2626" stroke-width="1.5"/>
          
          <circle cx="70" cy="40" r="2.5" fill="#ef4444" opacity="0.6"/>

          
          <polygon class="face-poly" points="40,40 70,65 70,115 40,90" fill="#fee2e2" stroke="#dc2626" stroke-width="1.5"/>
          
          <circle cx="50" cy="65" r="2.5" fill="#ef4444" opacity="0.6"/>
          <circle cx="60" cy="90" r="2.5" fill="#ef4444" opacity="0.6"/>

          
          <polygon class="face-poly" points="70,65 100,40 100,90 70,115" fill="#fca5a5" stroke="#dc2626" stroke-width="1.5"/>
          
          <circle cx="80" cy="65" r="2.5" fill="#ef4444" opacity="0.6"/>
          <circle cx="85" cy="77" r="2.5" fill="#ef4444" opacity="0.6"/>
          <circle cx="90" cy="90" r="2.5" fill="#ef4444" opacity="0.6"/>

          
          <circle class="vertex-dot" cx="70" cy="15" r="3" fill="#b91c1c"/>
          <circle class="vertex-dot" cx="100" cy="40" r="3" fill="#b91c1c"/>
          <circle class="vertex-dot" cx="70" cy="65" r="3" fill="#b91c1c"/>
          <circle class="vertex-dot" cx="40" cy="40" r="3" fill="#b91c1c"/>
          <circle class="vertex-dot" cx="40" cy="90" r="2" fill="#f87171" opacity="0.7"/>
          <circle class="vertex-dot" cx="70" cy="115" r="3" fill="#b91c1c"/>
          <circle class="vertex-dot" cx="100" cy="90" r="3" fill="#b91c1c"/>
        </svg>
      </div>

      <div class="prism-title">Cube</div>
      <div class="stats-list">
        <div class="stat-chip chip-f">6 Squares</div>
        <div class="stat-chip chip-v">8 Vertices</div>
        <div class="stat-chip chip-e">12 Edges</div>
      </div>
    </div>

    
    <div class="prism-card" style="border-top: 3px solid #38bdf8;">
      <span class="meta-tag tag-rect">🥣 Box</span>

      <div class="svg-wrap">
        <svg viewBox="0 0 140 120">
          
          <line class="edge-line" x1="45" y1="95" x2="45" y2="25" stroke="#bae6fd" stroke-dasharray="3,3" stroke-width="1.5"/>
          <line class="edge-line" x1="45" y1="25" x2="70" y2="10" stroke="#bae6fd" stroke-dasharray="3,3" stroke-width="1.5"/>
          <line class="edge-line" x1="45" y1="95" x2="95" y2="95" stroke="#bae6fd" stroke-dasharray="3,3" stroke-width="1.5"/>

          
          <polygon class="face-poly" points="70,10 95,25 70,40 45,25" fill="#e0f2fe" stroke="#0284c7" stroke-width="1.5"/>

          
          <polygon class="face-poly" points="45,25 70,40 70,110 45,95" fill="#bae6fd" stroke="#0284c7" stroke-width="1.5"/>
          
          <path d="M 52 75 Q 57.5 85 63 75 Z" fill="#0284c7" opacity="0.3"/>

          
          <polygon class="face-poly" points="70,40 95,25 95,95 70,110" fill="#7dd3fc" stroke="#0284c7" stroke-width="1.5"/>
          
          <line x1="78" y1="36" x2="78" y2="105" stroke="#0284c7" stroke-width="1" opacity="0.4"/>

          
          <circle class="vertex-dot" cx="70" cy="10" r="3" fill="#0369a1"/>
          <circle class="vertex-dot" cx="95" cy="25" r="3" fill="#0369a1"/>
          <circle class="vertex-dot" cx="70" cy="40" r="3" fill="#0369a1"/>
          <circle class="vertex-dot" cx="45" cy="25" r="3" fill="#0369a1"/>
          <circle class="vertex-dot" cx="45" cy="95" r="2" fill="#38bdf8" opacity="0.7"/>
          <circle class="vertex-dot" cx="70" cy="110" r="3" fill="#0369a1"/>
          <circle class="vertex-dot" cx="95" cy="95" r="3" fill="#0369a1"/>
        </svg>
      </div>

      <div class="prism-title">Rectangular<br>Prism</div>
      <div class="stats-list">
        <div class="stat-chip chip-f">6 Rectangles</div>
        <div class="stat-chip chip-v">8 Vertices</div>
        <div class="stat-chip chip-e">12 Edges</div>
      </div>
    </div>

    
    <div class="prism-card" style="border-top: 3px solid #4ade80;">
      <span class="meta-tag tag-tri">⛺ Tent</span>

      <div class="svg-wrap">
        <svg viewBox="0 0 140 120">
          
          <line class="edge-line" x1="80" y1="80" x2="35" y2="105" stroke="#bbf7d0" stroke-dasharray="3,3" stroke-width="1.5"/>
          <line class="edge-line" x1="80" y1="80" x2="115" y2="40" stroke="#bbf7d0" stroke-dasharray="3,3" stroke-width="1.5"/>

          
          <polygon class="face-poly" points="60,25 115,40 80,80 35,105" fill="#dcfce7" stroke="#16a34a" stroke-width="1.5"/>

          
          <polygon class="face-poly" points="60,25 35,105 85,115" fill="#86efac" stroke="#16a34a" stroke-width="1.5"/>
          
          <line x1="60" y1="25" x2="60" y2="110" stroke="#15803d" stroke-width="1.2" stroke-dasharray="2,2"/>

          
          <polygon class="face-poly" points="60,25 115,40 130,95 85,115" fill="#4ade80" stroke="#16a34a" stroke-width="1.5"/>

          
          <line class="edge-line" x1="115" y1="40" x2="130" y2="95" stroke="#16a34a" stroke-width="1.5"/>
          <line class="edge-line" x1="85" y1="115" x2="130" y2="95" stroke="#16a34a" stroke-width="1.5"/>

          
          <circle class="vertex-dot" cx="60" cy="25" r="3" fill="#15803d"/>
          <circle class="vertex-dot" cx="35" cy="105" r="3" fill="#15803d"/>
          <circle class="vertex-dot" cx="85" cy="115" r="3" fill="#15803d"/>
          <circle class="vertex-dot" cx="115" cy="40" r="3" fill="#15803d"/>
          <circle class="vertex-dot" cx="130" cy="95" r="3" fill="#15803d"/>
          <circle class="vertex-dot" cx="80" cy="80" r="2" fill="#4ade80" opacity="0.7"/>
        </svg>
      </div>

      <div class="prism-title">Triangular<br>Prism</div>
      <div class="stats-list">
        <div class="stat-chip chip-f">2 △ + 3 ▭ Faces</div>
        <div class="stat-chip chip-v">6 Vertices</div>
        <div class="stat-chip chip-e">9 Edges</div>
      </div>
    </div>

  </div>

  <script>
    // Audio synthesizer for gentle educational taps
    function playTone(freq, dur = 0.15) {
      try {
        const AudioCtx = window.AudioContext || window.webkitAudioContext;
        if (!AudioCtx) return;
        const ctx = new AudioCtx();
        const osc = ctx.createOscillator();
        const gain = ctx.createGain();
        osc.type = 'sine';
        osc.frequency.setValueAtTime(freq, ctx.currentTime);
        gain.gain.setValueAtTime(0.12, ctx.currentTime);
        gain.gain.exponentialRampToValueAtTime(0.001, ctx.currentTime + dur);
        osc.connect(gain);
        gain.connect(ctx.destination);
        osc.start();
        osc.stop(ctx.currentTime + dur);
      } catch (e) {}
    }

    const buttons = document.querySelectorAll('.tool-btn');
    const grid = document.getElementById('prismsGrid');
    const chipsFaces = document.querySelectorAll('.chip-f');
    const chipsVertices = document.querySelectorAll('.chip-v');
    const chipsEdges = document.querySelectorAll('.chip-e');

    const toneMap = {
      all: 440,
      faces: 523.25,      // C5
      vertices: 659.25,   // E5
      edges: 783.99       // G5
    };

    function setMode(mode) {
      // Toggle button states
      buttons.forEach(btn => {
        btn.classList.toggle('active', btn.dataset.mode === mode);
      });

      // Clear grid classes
      grid.className = 'grid';
      if (mode !== 'all') {
        grid.classList.add('mode-' + mode);
      }

      // Highlight corresponding stat chips
      chipsFaces.forEach(c => c.classList.toggle('hl-face', mode === 'faces'));
      chipsVertices.forEach(c => c.classList.toggle('hl-vertex', mode === 'vertices'));
      chipsEdges.forEach(c => c.classList.toggle('hl-edge', mode === 'edges'));
    }

    buttons.forEach(btn => {
      btn.addEventListener('click', () => {
        const mode = btn.dataset.mode;
        playTone(toneMap[mode]);
        setMode(mode);
      });
    });
  </script>
</body>
</html>

<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <meta name="aspect-ratio" content="1:1">
  <title>Parts of a Cube</title>
  <style>
    * {
      box-sizing: border-box;
      margin: 0;
      padding: 0;
    }

    body {
      width: 100%;
      font-family: system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
      color: #1e2945;
      background: #ffffff;
      display: flex;
      flex-direction: column;
      align-items: center;
      justify-content: space-between;
      padding: 12px 8px 8px;
    }

    .toolbar {
      display: flex;
      gap: 6px;
      margin-bottom: 4px;
      flex-wrap: wrap;
      justify-content: center;
      width: 100%;
      max-width: 350px;
    }

    .tab-btn {
      font-size: 13px;
      font-weight: 700;
      padding: 5px 10px;
      border-radius: 999px;
      border: 1.5px solid #e6e6e6;
      background: #f8fafc;
      color: #64748b;
      cursor: pointer;
      display: flex;
      align-items: center;
      gap: 5px;
      transition: all 0.2s ease;
    }

    .tab-btn .indicator {
      width: 8px;
      height: 8px;
      border-radius: 50%;
      display: inline-block;
    }

    .tab-btn[data-part="all"].active {
      background: #1e2945;
      color: #ffffff;
      border-color: #1e2945;
    }

    .tab-btn[data-part="face"].active {
      background: #fef08a;
      color: #854d0e;
      border-color: #eab308;
    }

    .tab-btn[data-part="edge"].active {
      background: #fee2e2;
      color: #991b1b;
      border-color: #ef4444;
    }

    .tab-btn[data-part="vertex"].active {
      background: #dcfce7;
      color: #166534;
      border-color: #22c55e;
    }

    .svg-container {
      width: 100%;
      max-width: 350px;
      aspect-ratio: 1 / 1;
      position: relative;
    }

    svg {
      width: 100%;
      height: 100%;
      overflow: visible;
    }

    /* Callout Card Styles inside SVG */
    .callout-box {
      rx: 8;
      ry: 8;
      filter: drop-shadow(0 2px 4px rgba(0,0,0,0.06));
    }

    .label-title {
      font-size: 13px;
      font-weight: 800;
    }

    .label-desc {
      font-size: 11px;
      font-weight: 500;
      fill: #475569;
    }

    /* Transition states */
    .interactive-part {
      cursor: pointer;
      transition: opacity 0.25s ease, stroke-width 0.25s ease;
    }

    .part-group {
      transition: opacity 0.25s ease;
    }

    .dimmed {
      opacity: 0.2;
    }

    .focused {
      opacity: 1;
    }

    .pointer-line {
      stroke-dasharray: 3 3;
    }
  </style>
</head>
<body>

  
  <div class="toolbar">
    <button class="tab-btn active" data-part="all">Show All</button>
    <button class="tab-btn" data-part="face">
      <span class="indicator" style="background:#eab308;"></span>Face
    </button>
    <button class="tab-btn" data-part="edge">
      <span class="indicator" style="background:#ef4444;"></span>Edge
    </button>
    <button class="tab-btn" data-part="vertex">
      <span class="indicator" style="background:#22c55e;"></span>Vertex
    </button>
  </div>

  
  <div class="svg-container">
    <svg viewBox="0 0 350 350">
      <defs>
        
        <ellipse id="cubeShadow" cx="175" cy="275" rx="85" ry="24" fill="#cbd5e1" opacity="0.45" />

        
        <filter id="glowYellow" x="-20%" y="-20%" width="140%" height="140%">
          <feDropShadow dx="0" dy="0" stdDeviation="3" flood-color="#facc15" flood-opacity="0.8"/>
        </filter>
        <filter id="glowRed" x="-20%" y="-20%" width="140%" height="140%">
          <feDropShadow dx="0" dy="0" stdDeviation="2.5" flood-color="#ef4444" flood-opacity="0.8"/>
        </filter>
        <filter id="glowGreen" x="-20%" y="-20%" width="140%" height="140%">
          <feDropShadow dx="0" dy="0" stdDeviation="3" flood-color="#22c55e" flood-opacity="0.9"/>
        </filter>
      </defs>

      
      <use href="#cubeShadow" />

      
      
      <polygon id="topFace" class="interactive-part"
               points="175,90 245,130 175,170 105,130"
               fill="#e0f2fe" stroke="#93c5fd" stroke-width="2" stroke-linejoin="round" />

      
      <polygon id="rightFace" class="interactive-part"
               points="175,170 245,130 245,220 175,260"
               fill="#bae6fd" stroke="#93c5fd" stroke-width="2" stroke-linejoin="round" />

      
      <g id="faceGroup" class="part-group">
        
        <polygon class="interactive-part"
                 points="105,130 175,170 175,260 105,220"
                 fill="#fef08a" stroke="#eab308" stroke-width="2.5" stroke-linejoin="round"
                 filter="url(#glowYellow)" />

        
        <polyline class="pointer-line" points="135,195 72,195" stroke="#ca8a04" stroke-width="1.8" fill="none" />
        <circle cx="135" cy="195" r="3.5" fill="#ca8a04" />

        
        <g transform="translate(6, 210)">
          <rect class="callout-box" x="0" y="0" width="128" height="42" fill="#fffbeb" stroke="#fcd34d" stroke-width="1.5" />
          <text class="label-title" x="8" y="17" fill="#854d0e">Face</text>
          <text class="label-desc" x="8" y="32">Flat surface</text>
        </g>
      </g>

      
      <g id="edgeGroup" class="part-group">
        
        <line class="interactive-part"
              x1="175" y1="170" x2="245" y2="130"
              stroke="#ef4444" stroke-width="5.5" stroke-linecap="round"
              filter="url(#glowRed)" />

        
        <polyline class="pointer-line" points="214,148 268,148 268,175" stroke="#dc2626" stroke-width="1.8" fill="none" />
        <circle cx="214" cy="148" r="3.5" fill="#dc2626" />

        
        <g transform="translate(194, 180)">
          <rect class="callout-box" x="0" y="0" width="150" height="42" fill="#fef2f2" stroke="#fca5a5" stroke-width="1.5" />
          <text class="label-title" x="8" y="17" fill="#991b1b">Edge</text>
          <text class="label-desc" x="8" y="32">Where 2 faces meet</text>
        </g>
      </g>

      
      <g id="vertexGroup" class="part-group">
        
        <circle class="interactive-part"
                cx="175" cy="90" r="7"
                fill="#22c55e" stroke="#15803d" stroke-width="2.5"
                filter="url(#glowGreen)" />

        
        <polyline class="pointer-line" points="175,83 175,44 195,44" stroke="#16a34a" stroke-width="1.8" fill="none" />
        <circle cx="175" cy="83" r="3" fill="#16a34a" />

        
        <g transform="translate(196, 22)">
          <rect class="callout-box" x="0" y="0" width="138" height="42" fill="#f0fdf4" stroke="#86efac" stroke-width="1.5" />
          <text class="label-title" x="8" y="17" fill="#166534">Vertex</text>
          <text class="label-desc" x="8" y="32">Pointy corner</text>
        </g>
      </g>
    </svg>
  </div>

  <script>
    // Audio synthesis on tap for tactile Grade 1-2 learning
    function playTone(freq, type = 'sine') {
      try {
        const ctx = new (window.AudioContext || window.webkitAudioContext)();
        const osc = ctx.createOscillator();
        const gain = ctx.createGain();
        osc.type = type;
        osc.frequency.value = freq;
        osc.connect(gain);
        gain.connect(ctx.destination);
        gain.gain.setValueAtTime(0.18, ctx.currentTime);
        gain.gain.exponentialRampToValueAtTime(0.001, ctx.currentTime + 0.25);
        osc.start();
        osc.stop(ctx.currentTime + 0.25);
      } catch (e) {}
    }

    const tones = {
      face: 392.00,   // G4
      edge: 523.25,   // C5
      vertex: 659.25, // E5
      all: 440.00     // A4
    };

    const buttons = document.querySelectorAll('.tab-btn');
    const groups = {
      face: document.getElementById('faceGroup'),
      edge: document.getElementById('edgeGroup'),
      vertex: document.getElementById('vertexGroup')
    };

    function setMode(mode) {
      playTone(tones[mode] || 440);

      // Update button state
      buttons.forEach(btn => {
        if (btn.dataset.part === mode) {
          btn.classList.add('active');
        } else {
          btn.classList.remove('active');
        }
      });

      // Update visibility of groups
      Object.keys(groups).forEach(key => {
        const grp = groups[key];
        if (mode === 'all' || mode === key) {
          grp.classList.remove('dimmed');
          grp.classList.add('focused');
        } else {
          grp.classList.add('dimmed');
          grp.classList.remove('focused');
        }
      });
    }

    buttons.forEach(btn => {
      btn.addEventListener('click', () => setMode(btn.dataset.part));
    });

    // Make elements directly tappable
    document.getElementById('faceGroup').addEventListener('click', () => setMode('face'));
    document.getElementById('edgeGroup').addEventListener('click', () => setMode('edge'));
    document.getElementById('vertexGroup').addEventListener('click', () => setMode('vertex'));
  </script>
</body>
</html>

<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <meta name="aspect-ratio" content="1:1">
  <style>
    * {
      box-sizing: border-box;
      margin: 0;
      padding: 0;
    }
    body {
      font-family: system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
      background: #ffffff;
      color: #1e2945;
      padding: 10px;
      display: flex;
      flex-direction: column;
      gap: 8px;
    }
    /* Toolbar / Filter */
    .filter-bar {
      display: flex;
      justify-content: center;
      gap: 6px;
      margin-bottom: 2px;
    }
    .filter-btn {
      border: 1.5px solid #e2e8f0;
      background: #f8fafc;
      color: #475569;
      font-size: 13px;
      font-weight: 700;
      padding: 5px 12px;
      border-radius: 20px;
      cursor: pointer;
      display: flex;
      align-items: center;
      gap: 5px;
      transition: background-color 0.2s, border-color 0.2s, color 0.2s;
    }
    .filter-btn.active {
      background: #1e2945;
      color: #ffffff;
      border-color: #1e2945;
    }
    .legend-dot {
      width: 8px;
      height: 8px;
      border-radius: 50%;
      display: inline-block;
    }
    .legend-dot.vertex { background: #ef4444; }
    .legend-dot.side { background: #2563eb; }

    /* 2x2 Grid */
    .grid {
      display: grid;
      grid-template-columns: repeat(2, 1fr);
      gap: 8px;
      width: 100%;
    }
    .shape-card {
      background: #f8fafc;
      border: 2px solid #e2e8f0;
      border-radius: 12px;
      padding: 8px 6px;
      display: flex;
      flex-direction: column;
      align-items: center;
      text-align: center;
      transition: box-shadow 0.2s, border-color 0.2s;
    }
    .shape-card:hover {
      border-color: #cbd5e1;
      box-shadow: 0 3px 10px rgba(0,0,0,0.05);
    }
    .card-title {
      font-size: 14px;
      font-weight: 800;
      color: #0f172a;
      line-height: 1.2;
    }
    .card-stats {
      display: flex;
      gap: 6px;
      font-size: 12px;
      font-weight: 700;
      margin-top: 2px;
      margin-bottom: 4px;
    }
    .stat-tag {
      padding: 1px 6px;
      border-radius: 6px;
      transition: opacity 0.2s;
    }
    .stat-tag.sides {
      background: #dbeafe;
      color: #1d4ed8;
    }
    .stat-tag.verts {
      background: #fee2e2;
      color: #b91c1c;
    }
    .svg-wrap {
      width: 100%;
      max-width: 125px;
      aspect-ratio: 1 / 1;
      display: flex;
      align-items: center;
      justify-content: center;
    }
    svg {
      width: 100%;
      height: 100%;
      overflow: visible;
    }

    /* Shape Styling */
    .poly-base {
      stroke-width: 3.5;
      stroke-linejoin: round;
      stroke-linecap: round;
    }
    .c-blue { fill: #e0f2fe; stroke: #0284c7; }
    .c-amber { fill: #fef3c7; stroke: #d97706; }
    .c-emerald { fill: #d1fae5; stroke: #059669; }
    .c-purple { fill: #ede9fe; stroke: #7c3aed; }

    /* Side indicators */
    .side-pill {
      font-size: 8.5px;
      font-weight: 800;
      fill: #1d4ed8;
      text-anchor: middle;
      dominant-baseline: central;
      transition: opacity 0.2s;
    }
    .side-bg {
      fill: #eff6ff;
      stroke: #93c5fd;
      stroke-width: 1;
      transition: opacity 0.2s;
    }

    /* Vertex dots */
    .v-dot {
      fill: #ef4444;
      stroke: #ffffff;
      stroke-width: 1.5;
      transition: transform 0.2s, opacity 0.2s;
    }

    /* Dimming modes */
    body[data-mode="sides"] .verts-group,
    body[data-mode="sides"] .stat-tag.verts {
      opacity: 0.15;
    }
    body[data-mode="verts"] .sides-group,
    body[data-mode="verts"] .stat-tag.sides {
      opacity: 0.15;
    }
  </style>
</head>
<body data-mode="all">

  
  <div class="filter-bar">
    <button class="filter-btn active" data-view="all">✦ All</button>
    <button class="filter-btn" data-view="sides">
      <span class="legend-dot side"></span>Sides
    </button>
    <button class="filter-btn" data-view="verts">
      <span class="legend-dot vertex"></span>Vertices
    </button>
  </div>

  
  <div class="grid">

    
    <div class="shape-card">
      <div class="card-title">Circle</div>
      <div class="card-stats">
        <span class="stat-tag sides">0 sides</span>
        <span class="stat-tag verts">0 vertices</span>
      </div>
      <div class="svg-wrap">
        <svg viewBox="0 0 100 100">
          <circle cx="50" cy="50" r="36" class="poly-base c-blue" />
        </svg>
      </div>
    </div>

    
    <div class="shape-card">
      <div class="card-title">Triangle</div>
      <div class="card-stats">
        <span class="stat-tag sides">3 sides</span>
        <span class="stat-tag verts">3 vertices</span>
      </div>
      <div class="svg-wrap">
        <svg viewBox="0 0 100 100">
          <polygon points="50,16 16,80 84,80" class="poly-base c-amber" />
          
          
          <g class="sides-group">
            
            <circle cx="28" cy="46" r="6.5" class="side-bg" />
            <text x="28" y="46" class="side-pill">1</text>
            
            <circle cx="50" cy="87" r="6.5" class="side-bg" />
            <text x="50" y="87" class="side-pill">2</text>
            
            <circle cx="72" cy="46" r="6.5" class="side-bg" />
            <text x="72" y="46" class="side-pill">3</text>
          </g>

          
          <g class="verts-group">
            <circle cx="50" cy="16" r="4.5" class="v-dot" />
            <circle cx="16" cy="80" r="4.5" class="v-dot" />
            <circle cx="84" cy="80" r="4.5" class="v-dot" />
          </g>
        </svg>
      </div>
    </div>

    
    <div class="shape-card">
      <div class="card-title">Rectangle & Square</div>
      <div class="card-stats">
        <span class="stat-tag sides">4 sides</span>
        <span class="stat-tag verts">4 vertices</span>
      </div>
      <div class="svg-wrap">
        <svg viewBox="0 0 100 100">
          <rect x="15" y="24" width="70" height="52" rx="2" class="poly-base c-emerald" />
          
          
          <g class="sides-group">
            
            <circle cx="50" cy="17" r="6.5" class="side-bg" />
            <text x="50" y="17" class="side-pill">1</text>
            
            <circle cx="91" cy="50" r="6.5" class="side-bg" />
            <text x="91" y="50" class="side-pill">2</text>
            
            <circle cx="50" cy="83" r="6.5" class="side-bg" />
            <text x="50" y="83" class="side-pill">3</text>
            
            <circle cx="9" cy="50" r="6.5" class="side-bg" />
            <text x="9" y="50" class="side-pill">4</text>
          </g>

          
          <g class="verts-group">
            <circle cx="15" cy="24" r="4.5" class="v-dot" />
            <circle cx="85" cy="24" r="4.5" class="v-dot" />
            <circle cx="85" cy="76" r="4.5" class="v-dot" />
            <circle cx="15" cy="76" r="4.5" class="v-dot" />
          </g>
        </svg>
      </div>
    </div>

    
    <div class="shape-card">
      <div class="card-title">Hexagon</div>
      <div class="card-stats">
        <span class="stat-tag sides">6 sides</span>
        <span class="stat-tag verts">6 vertices</span>
      </div>
      <div class="svg-wrap">
        <svg viewBox="0 0 100 100">
          <polygon points="50,15 82,33 82,67 50,85 18,67 18,33" class="poly-base c-purple" />
          
          
          <g class="sides-group">
            
            <circle cx="70" cy="21" r="6.5" class="side-bg" />
            <text x="70" y="21" class="side-pill">1</text>
            
            <circle cx="89" cy="50" r="6.5" class="side-bg" />
            <text x="89" y="50" class="side-pill">2</text>
            
            <circle cx="70" cy="79" r="6.5" class="side-bg" />
            <text x="70" y="79" class="side-pill">3</text>
            
            <circle cx="30" cy="79" r="6.5" class="side-bg" />
            <text x="30" y="79" class="side-pill">4</text>
            
            <circle cx="11" cy="50" r="6.5" class="side-bg" />
            <text x="11" y="50" class="side-pill">5</text>
            
            <circle cx="30" cy="21" r="6.5" class="side-bg" />
            <text x="30" y="21" class="side-pill">6</text>
          </g>

          
          <g class="verts-group">
            <circle cx="50" cy="15" r="4.5" class="v-dot" />
            <circle cx="82" cy="33" r="4.5" class="v-dot" />
            <circle cx="82" cy="67" r="4.5" class="v-dot" />
            <circle cx="50" cy="85" r="4.5" class="v-dot" />
            <circle cx="18" cy="67" r="4.5" class="v-dot" />
            <circle cx="18" cy="33" r="4.5" class="v-dot" />
          </g>
        </svg>
      </div>
    </div>

  </div>

  <script>
    const buttons = document.querySelectorAll('.filter-btn');
    buttons.forEach(btn => {
      btn.addEventListener('click', () => {
        buttons.forEach(b => b.classList.remove('active'));
        btn.classList.add('active');
        document.body.setAttribute('data-mode', btn.getAttribute('data-view'));
      });
    });
  </script>
</body>
</html>

Sorting Flat Shapes by Sides and Vertices

<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <meta name="aspect-ratio" content="4:3">
  <style>
    * { box-sizing: border-box; margin: 0; padding: 0; }
    body {
      font-family: system-ui, -apple-system, sans-serif;
      background: #ffffff;
      color: #1e2945;
      display: flex;
      flex-direction: column;
      align-items: center;
      justify-content: flex-start;
      width: 100%;
      padding: 8px;
      user-select: none;
    }
    .controls {
      display: flex;
      gap: 6px;
      margin-bottom: 6px;
      flex-wrap: wrap;
      justify-content: center;
    }
    .btn {
      padding: 6px 12px;
      font-size: 13px;
      font-weight: 600;
      border-radius: 8px;
      border: 1px solid #d1d5db;
      background: #f8fafc;
      color: #374151;
      cursor: pointer;
      transition: all 0.2s ease;
    }
    .btn:hover {
      background: #f1f5f9;
      border-color: #9ca3af;
    }
    .btn.active {
      background: #0284c7;
      color: #ffffff;
      border-color: #0284c7;
    }
    svg {
      width: 100%;
      max-width: 620px;
      height: auto;
      display: block;
    }
    .guide-path {
      stroke-dasharray: 6 6;
      fill: none;
      stroke-width: 2.5;
      opacity: 0.35;
      transition: opacity 0.3s ease;
    }
    .guide-path.active {
      opacity: 1;
    }
    .shape-node {
      cursor: pointer;
      transition: transform 0.8s cubic-bezier(0.34, 1.3, 0.64, 1);
    }
    .bin-group {
      cursor: pointer;
      transition: transform 0.2s ease, filter 0.2s ease;
    }
    .bin-group:hover {
      filter: brightness(0.96);
    }
  </style>
</head>
<body>

  <div class="controls">
    <button class="btn" id="btnAll" onclick="setStep('all')">Sort All</button>
    <button class="btn" id="btn0" onclick="setStep('0')">0 Sides</button>
    <button class="btn" id="btn3" onclick="setStep('3')">3 Sides</button>
    <button class="btn" id="btn4" onclick="setStep('4')">4 Sides</button>
    <button class="btn" id="btnReset" onclick="setStep('reset')">Reset ↺</button>
  </div>

  <svg viewBox="0 0 600 420" xmlns="http://www.w3.org/2000/svg">
    <defs>
      <marker id="arrow-red" viewBox="0 0 10 10" refX="6" refY="5" markerWidth="6" markerHeight="6" orient="auto">
        <path d="M 0 1 L 10 5 L 0 9 z" fill="#ef4444" />
      </marker>
      <marker id="arrow-blue" viewBox="0 0 10 10" refX="6" refY="5" markerWidth="6" markerHeight="6" orient="auto">
        <path d="M 0 1 L 10 5 L 0 9 z" fill="#0284c7" />
      </marker>
      <marker id="arrow-yellow" viewBox="0 0 10 10" refX="6" refY="5" markerWidth="6" markerHeight="6" orient="auto">
        <path d="M 0 1 L 10 5 L 0 9 z" fill="#d97706" />
      </marker>
      <marker id="arrow-orange" viewBox="0 0 10 10" refX="6" refY="5" markerWidth="6" markerHeight="6" orient="auto">
        <path d="M 0 1 L 10 5 L 0 9 z" fill="#ea580c" />
      </marker>
      <marker id="arrow-purple" viewBox="0 0 10 10" refX="6" refY="5" markerWidth="6" markerHeight="6" orient="auto">
        <path d="M 0 1 L 10 5 L 0 9 z" fill="#8b5cf6" />
      </marker>
    </defs>

    
    
    <path id="path-s1" class="guide-path active" stroke="#ef4444" marker-end="url(#arrow-red)"
          d="M 170 65 C 130 140, 100 200, 100 300" />

    
    <path id="path-s2" class="guide-path active" stroke="#0284c7" marker-end="url(#arrow-blue)"
          d="M 70 70 C 110 150, 240 180, 255 305" />

    
    <path id="path-s3" class="guide-path active" stroke="#d97706" marker-end="url(#arrow-yellow)"
          d="M 470 70 C 430 150, 360 200, 345 310" />

    
    <path id="path-s4" class="guide-path active" stroke="#ea580c" marker-end="url(#arrow-orange)"
          d="M 295 75 C 330 150, 440 180, 455 305" />

    
    <path id="path-s5" class="guide-path active" stroke="#8b5cf6" marker-end="url(#arrow-purple)"
          d="M 395 75 C 440 140, 530 190, 545 305" />

    
    
    <g class="bin-group" onclick="setStep('0')">
      <rect x="15" y="270" width="170" height="135" rx="14" fill="#f0f9ff" stroke="#38bdf8" stroke-width="3" />
      <rect x="15" y="270" width="170" height="16" rx="8" fill="#bae6fd" />
      <text x="100" y="380" font-size="14" font-weight="700" fill="#0369a1" text-anchor="middle">0 Sides &amp;</text>
      <text x="100" y="398" font-size="14" font-weight="700" fill="#0369a1" text-anchor="middle">0 Vertices</text>
    </g>

    
    <g class="bin-group" onclick="setStep('3')">
      <rect x="215" y="270" width="170" height="135" rx="14" fill="#fffbeb" stroke="#f59e0b" stroke-width="3" />
      <rect x="215" y="270" width="170" height="16" rx="8" fill="#fde68a" />
      <text x="300" y="380" font-size="14" font-weight="700" fill="#b45309" text-anchor="middle">3 Sides &amp;</text>
      <text x="300" y="398" font-size="14" font-weight="700" fill="#b45309" text-anchor="middle">3 Vertices</text>
    </g>

    
    <g class="bin-group" onclick="setStep('4')">
      <rect x="415" y="270" width="170" height="135" rx="14" fill="#faf5ff" stroke="#a855f7" stroke-width="3" />
      <rect x="415" y="270" width="170" height="16" rx="8" fill="#e9d5ff" />
      <text x="500" y="380" font-size="14" font-weight="700" fill="#7e22ce" text-anchor="middle">4 Sides &amp;</text>
      <text x="500" y="398" font-size="14" font-weight="700" fill="#7e22ce" text-anchor="middle">4 Vertices</text>
    </g>

    
    
    <g id="s1" class="shape-node" onclick="toggleShape(1)">
      <circle cx="170" cy="50" r="24" fill="#ef4444" stroke="#b91c1c" stroke-width="2.5" />
    </g>

    
    <g id="s2" class="shape-node" onclick="toggleShape(2)">
      <polygon points="60,25 35,70 85,70" fill="#0284c7" stroke="#0369a1" stroke-width="2.5" stroke-linejoin="round" />
    </g>

    
    <g id="s3" class="shape-node" onclick="toggleShape(3)">
      <polygon points="480,32 435,72 525,72" fill="#fbbf24" stroke="#d97706" stroke-width="2.5" stroke-linejoin="round" />
    </g>

    
    <g id="s4" class="shape-node" onclick="toggleShape(4)">
      <rect x="277" y="24" width="28" height="52" rx="4" fill="#fb923c" stroke="#c2410c" stroke-width="2.5" />
    </g>

    
    <g id="s5" class="shape-node" onclick="toggleShape(5)">
      <polygon points="390,26 414,50 390,74 366,50" fill="#a855f7" stroke="#7e22ce" stroke-width="2.5" stroke-linejoin="round" />
    </g>
  </svg>

  <script>
    // Offsets to move shapes from top position to inside their corresponding bins
    const sortedOffsets = {
      1: { x: -70, y: 270 }, // S1 Circle -> Bin 1 (cx: 100, cy: 320)
      2: { x: 195, y: 275 }, // S2 Blue Tri -> Bin 2 (center x: 255, y: 325)
      3: { x: -135, y: 278 },// S3 Yellow Tri -> Bin 2 (center x: 345, y: 330)
      4: { x: 164, y: 276 }, // S4 Orange Rect -> Bin 3 (center x: 455, y: 325)
      5: { x: 155, y: 275 }  // S5 Purple Diamond -> Bin 3 (center x: 545, y: 325)
    };

    let shapeStates = { 1: true, 2: true, 3: true, 4: true, 5: true };

    function updateView() {
      for (let i = 1; i <= 5; i++) {
        const el = document.getElementById('s' + i);
        const path = document.getElementById('path-s' + i);
        if (shapeStates[i]) {
          const off = sortedOffsets[i];
          el.style.transform = `translate(${off.x}px, ${off.y}px)`;
          path.classList.add('active');
        } else {
          el.style.transform = 'translate(0px, 0px)';
          path.classList.remove('active');
        }
      }
    }

    function setStep(mode) {
      document.querySelectorAll('.btn').forEach(b => b.classList.remove('active'));
      if (mode === 'all') {
        shapeStates = { 1: true, 2: true, 3: true, 4: true, 5: true };
        document.getElementById('btnAll').classList.add('active');
      } else if (mode === 'reset') {
        shapeStates = { 1: false, 2: false, 3: false, 4: false, 5: false };
        document.getElementById('btnReset').classList.add('active');
      } else if (mode === '0') {
        shapeStates = { 1: true, 2: false, 3: false, 4: false, 5: false };
        document.getElementById('btn0').classList.add('active');
      } else if (mode === '3') {
        shapeStates = { 1: false, 2: true, 3: true, 4: false, 5: false };
        document.getElementById('btn3').classList.add('active');
      } else if (mode === '4') {
        shapeStates = { 1: false, 2: false, 3: false, 4: true, 5: true };
        document.getElementById('btn4').classList.add('active');
      }
      updateView();
    }

    function toggleShape(id) {
      shapeStates[id] = !shapeStates[id];
      document.querySelectorAll('.btn').forEach(b => b.classList.remove('active'));
      updateView();
    }

    // Initialize with all shapes sorted
    setStep('all');
  </script>
</body>
</html>

111.3(b)(1)(G)

Aligned learning resources

Related diagrams