<!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: #fdfbf7;
      color: #1e2945;
      display: flex;
      flex-direction: column;
      align-items: center;
      justify-content: space-between;
      min-height: 100%;
      padding: 12px;
      user-select: none;
    }

    .toolbar {
      display: flex;
      flex-wrap: wrap;
      gap: 6px;
      justify-content: center;
      margin-bottom: 8px;
    }

    .btn-tab {
      background: #ffffff;
      border: 1.5px solid #e2e8f0;
      border-radius: 20px;
      padding: 6px 12px;
      font-size: 13px;
      font-weight: 600;
      color: #475569;
      cursor: pointer;
      display: inline-flex;
      align-items: center;
      gap: 5px;
      transition: background 0.2s, border-color 0.2s, color 0.2s, box-shadow 0.2s;
    }
    .btn-tab.active {
      background: #2563eb;
      border-color: #2563eb;
      color: #ffffff;
      box-shadow: 0 2px 6px rgba(37,99,235,0.25);
    }

    .stage-container {
      width: 100%;
      max-width: 520px;
      flex: 1;
      display: flex;
      align-items: center;
      justify-content: center;
    }

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

    /* Side lines styling */
    .side {
      stroke-width: 5;
      stroke-linecap: round;
      transition: stroke-width 0.3s, opacity 0.3s;
    }
    .side-blue   { stroke: #2563eb; }
    .side-orange { stroke: #ea580c; }
    .side-green  { stroke: #16a34a; }

    .tick {
      stroke-width: 2.5;
      stroke-linecap: round;
    }

    .dimmed {
      opacity: 0.2;
    }

    .highlighted {
      stroke-width: 8;
      filter: drop-shadow(0 0 4px rgba(0,0,0,0.15));
    }

    /* Vertex Stars */
    .vertex-star {
      transform-origin: center;
      transition: transform 0.3s ease, opacity 0.3s ease;
      animation: pulse-star 1.8s ease-in-out infinite;
    }

    @keyframes pulse-star {
      0%, 100% { transform: scale(1); }
      50% { transform: scale(1.22); }
    }

    /* Triangle labels */
    .label-text {
      font-size: 15px;
      font-weight: 800;
      fill: #1e2945;
    }

    .triangle-title {
      font-size: 14px;
      font-weight: 700;
      fill: #64748b;
      letter-spacing: 0.5px;
    }

    /* Bottom banner */
    .banner {
      width: 100%;
      max-width: 520px;
      background: #eff6ff;
      border: 1.5px solid #bfdbfe;
      border-radius: 12px;
      padding: 9px 14px;
      text-align: center;
      font-size: 14px;
      font-weight: 700;
      color: #1d4ed8;
      margin-top: 8px;
      box-shadow: 0 1px 3px rgba(0,0,0,0.03);
    }
  </style>
</head>
<body>

  
  <div class="toolbar">
    <button class="btn-tab active" data-mode="all">✦ All Matches</button>
    <button class="btn-tab" data-mode="corners">⭐ Corners</button>
    <button class="btn-tab" data-mode="side1">― Side 1 (Blue)</button>
    <button class="btn-tab" data-mode="side2">⚌ Side 2 (Orange)</button>
    <button class="btn-tab" data-mode="side3">⚞ Side 3 (Green)</button>
  </div>

  
  <div class="stage-container">
    <svg viewBox="0 0 460 230" aria-label="Two congruent triangles ABC and DEF with matching sides and corners">
      <defs>
        
        <linearGradient id="fillA" x1="0%" y1="0%" x2="100%" y2="100%">
          <stop offset="0%" stop-color="#f0fdf4" stop-opacity="0.8"/>
          <stop offset="100%" stop-color="#eff6ff" stop-opacity="0.8"/>
        </linearGradient>
        <linearGradient id="fillB" x1="0%" y1="0%" x2="100%" y2="100%">
          <stop offset="0%" stop-color="#f0fdf4" stop-opacity="0.8"/>
          <stop offset="100%" stop-color="#eff6ff" stop-opacity="0.8"/>
        </linearGradient>
      </defs>

      
      
      
      <polygon points="80,42 35,175 175,160" fill="url(#fillA)" stroke="#e2e8f0" stroke-width="1.5" />

      
      <line id="side-ab" class="side side-blue" x1="80" y1="42" x2="35" y2="175" />
      <line class="tick side-blue tick-s1" x1="53" y1="105" x2="63" y2="110" />

      
      <line id="side-bc" class="side side-orange" x1="35" y1="175" x2="175" y2="160" />
      <line class="tick side-orange tick-s2" x1="102" y1="162" x2="100" y2="173" />
      <line class="tick side-orange tick-s2" x1="107" y1="162" x2="105" y2="173" />

      
      <line id="side-ca" class="side side-green" x1="175" y1="160" x2="80" y2="42" />
      <line class="tick side-green tick-s3" x1="125" y1="97" x2="134" y2="104" />
      <line class="tick side-green tick-s3" x1="128" y1="101" x2="137" y2="108" />
      <line class="tick side-green tick-s3" x1="131" y1="105" x2="140" y2="112" />

      
      <text x="100" y="212" text-anchor="middle" class="triangle-title">Triangle ABC</text>

      
      <text x="80" y="28" text-anchor="middle" class="label-text">A</text>
      <text x="20" y="185" text-anchor="middle" class="label-text">B</text>
      <text x="190" y="170" text-anchor="middle" class="label-text">C</text>

      
      <g class="vertex-star star-corner" style="transform-origin: 80px 42px;">
        <circle cx="80" cy="42" r="5" fill="#f59e0b"/>
        <circle cx="80" cy="42" r="10" fill="#fbbf24" opacity="0.35"/>
      </g>
      <g class="vertex-star star-corner" style="transform-origin: 35px 175px;">
        <circle cx="35" cy="175" r="5" fill="#f59e0b"/>
        <circle cx="35" cy="175" r="10" fill="#fbbf24" opacity="0.35"/>
      </g>
      <g class="vertex-star star-corner" style="transform-origin: 175px 160px;">
        <circle cx="175" cy="160" r="5" fill="#f59e0b"/>
        <circle cx="175" cy="160" r="10" fill="#fbbf24" opacity="0.35"/>
      </g>


      
      <g transform="translate(230, 110)">
        <circle cx="0" cy="0" r="18" fill="#ffffff" stroke="#cbd5e1" stroke-width="1.5" />
        <text x="0" y="6" text-anchor="middle" font-size="20" font-weight="900" fill="#2563eb">≅</text>
      </g>


      
      
      <polygon points="320,42 275,175 415,160" fill="url(#fillB)" stroke="#e2e8f0" stroke-width="1.5" />

      
      <line id="side-de" class="side side-blue" x1="320" y1="42" x2="275" y2="175" />
      <line class="tick side-blue tick-s1" x1="293" y1="105" x2="303" y2="110" />

      
      <line id="side-ef" class="side side-orange" x1="275" y1="175" x2="415" y2="160" />
      <line class="tick side-orange tick-s2" x1="342" y1="162" x2="340" y2="173" />
      <line class="tick side-orange tick-s2" x1="347" y1="162" x2="345" y2="173" />

      
      <line id="side-fd" class="side side-green" x1="415" y1="160" x2="320" y2="42" />
      <line class="tick side-green tick-s3" x1="365" y1="97" x2="374" y2="104" />
      <line class="tick side-green tick-s3" x1="368" y1="101" x2="377" y2="108" />
      <line class="tick side-green tick-s3" x1="371" y1="105" x2="380" y2="112" />

      
      <text x="340" y="212" text-anchor="middle" class="triangle-title">Triangle DEF</text>

      
      <text x="320" y="28" text-anchor="middle" class="label-text">D</text>
      <text x="260" y="185" text-anchor="middle" class="label-text">E</text>
      <text x="430" y="170" text-anchor="middle" class="label-text">F</text>

      
      <g class="vertex-star star-corner" style="transform-origin: 320px 42px;">
        <circle cx="320" cy="42" r="5" fill="#f59e0b"/>
        <circle cx="320" cy="42" r="10" fill="#fbbf24" opacity="0.35"/>
      </g>
      <g class="vertex-star star-corner" style="transform-origin: 275px 175px;">
        <circle cx="275" cy="175" r="5" fill="#f59e0b"/>
        <circle cx="275" cy="175" r="10" fill="#fbbf24" opacity="0.35"/>
      </g>
      <g class="vertex-star star-corner" style="transform-origin: 415px 160px;">
        <circle cx="415" cy="160" r="5" fill="#f59e0b"/>
        <circle cx="415" cy="160" r="10" fill="#fbbf24" opacity="0.35"/>
      </g>
    </svg>
  </div>

  
  <div class="banner">
    Matching Corners &amp; Matching Sides = Congruent!
  </div>

  <script>
    const buttons = document.querySelectorAll('.btn-tab');
    const s1Elements = document.querySelectorAll('.side-blue');
    const s2Elements = document.querySelectorAll('.side-orange');
    const s3Elements = document.querySelectorAll('.side-green');
    const cornerElements = document.querySelectorAll('.star-corner');

    const allGroups = [
      { id: 'side1', els: s1Elements },
      { id: 'side2', els: s2Elements },
      { id: 'side3', els: s3Elements },
      { id: 'corners', els: cornerElements }
    ];

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

      if (mode === 'all') {
        allGroups.forEach(g => {
          g.els.forEach(el => {
            el.classList.remove('dimmed', 'highlighted');
          });
        });
      } else {
        allGroups.forEach(g => {
          const match = g.id === mode;
          g.els.forEach(el => {
            el.classList.toggle('dimmed', !match);
            el.classList.toggle('highlighted', match);
          });
        });
      }
    }

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

Matching Congruent Shapes by Size and Shape

<!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%;
      height: 100%;
      background: #fdfbf7;
      font-family: system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
      color: #2d3748;
      display: flex;
      flex-direction: column;
      align-items: center;
      justify-content: space-between;
      padding: 16px;
      user-select: none;
    }

    .stage {
      position: relative;
      width: 100%;
      max-width: 480px;
      height: 240px;
      background: #ffffff;
      border-radius: 16px;
      box-shadow: 0 4px 16px rgba(140, 120, 200, 0.08);
      display: flex;
      align-items: center;
      justify-content: center;
      overflow: hidden;
    }

    .grid-dots {
      position: absolute;
      inset: 0;
      background-image: radial-gradient(#e2e8f0 1.5px, transparent 1.5px);
      background-size: 24px 24px;
      background-position: center;
      opacity: 0.8;
    }

    /* SVG Canvas */
    .scene-svg {
      width: 100%;
      height: 100%;
      overflow: visible;
    }

    /* Target Slot */
    .target-slot {
      fill: #f1edfa;
      stroke: #c4b5fd;
      stroke-width: 3;
      stroke-dasharray: 6 6;
      rx: 6px;
    }

    /* Moving L-Piece */
    .moving-piece {
      transform-origin: 0px 0px;
      transition: transform 0.8s cubic-bezier(0.34, 1.3, 0.64, 1), filter 0.4s ease;
      cursor: pointer;
    }

    .l-block {
      fill: #8b5cf6;
      stroke: #7c3aed;
      stroke-width: 2.5;
      rx: 6px;
    }

    /* Grid lines inside piece */
    .inner-line {
      stroke: rgba(255, 255, 255, 0.35);
      stroke-width: 2;
    }

    /* Glow & Sparkles */
    .sparkle {
      opacity: 0;
      transform-origin: center;
      transition: opacity 0.4s ease, transform 0.4s ease;
    }

    .matched .sparkle {
      opacity: 1;
      animation: popSparkle 1.2s ease-in-out infinite alternate;
    }

    .matched .moving-piece {
      filter: drop-shadow(0 0 12px rgba(168, 85, 247, 0.5));
    }

    @keyframes popSparkle {
      0% { transform: scale(0.85) rotate(0deg); }
      100% { transform: scale(1.15) rotate(15deg); }
    }

    /* Feedback Banner */
    .status-badge {
      font-size: 16px;
      font-weight: 700;
      color: #6d28d9;
      background: #ede9fe;
      padding: 6px 16px;
      border-radius: 20px;
      min-height: 36px;
      display: flex;
      align-items: center;
      gap: 6px;
      transition: all 0.3s ease;
    }

    /* Stepper Controls */
    .controls {
      display: flex;
      align-items: center;
      gap: 8px;
      margin-top: 10px;
    }

    .step-btn {
      background: #f3f4f6;
      border: 2px solid rgba(0,0,0,0);
      color: #4b5563;
      padding: 6px 14px;
      border-radius: 999px;
      font-size: 14px;
      font-weight: 600;
      cursor: pointer;
      display: flex;
      align-items: center;
      gap: 4px;
      transition: background 0.2s, color 0.2s, box-shadow 0.2s;
    }

    .step-btn.active {
      background: #8b5cf6;
      color: #ffffff;
      box-shadow: 0 2px 8px rgba(139, 92, 246, 0.35);
    }

    .play-btn {
      background: #ffffff;
      border: 2px solid #e5e7eb;
      color: #6b7280;
      width: 36px;
      height: 36px;
      border-radius: 50%;
      display: flex;
      align-items: center;
      justify-content: center;
      font-size: 14px;
      cursor: pointer;
      margin-left: 4px;
    }
  </style>
</head>
<body>

  
  <div class="status-badge" id="statusLabel">
    <span>✦</span> <span id="labelText">Turned Around</span>
  </div>

  
  <div class="stage">
    <div class="grid-dots"></div>

    <svg class="scene-svg" viewBox="0 0 400 200" id="sceneSvg">
      
      <g id="targetGroup" transform="translate(80, 40)">
        
        <path class="target-slot" d="M 0 0 L 40 0 L 40 80 L 80 80 L 80 120 L 0 120 Z" />
      </g>

      
      <g id="sparklesGroup" transform="translate(80, 40)">
        <text class="sparkle" x="-15" y="15" font-size="20">✨</text>
        <text class="sparkle" x="85" y="60" font-size="22">⭐</text>
        <text class="sparkle" x="70" y="135" font-size="18">✨</text>
        <text class="sparkle" x="-10" y="115" font-size="18">⭐</text>
      </g>

      
      
      <g id="movingPiece" class="moving-piece">
        <g transform="translate(-40, -60)">
          
          <path class="l-block" d="M 0 0 L 40 0 L 40 80 L 80 80 L 80 120 L 0 120 Z" />
          
          <line class="inner-line" x1="0" y1="40" x2="40" y2="40" />
          <line class="inner-line" x1="0" y1="80" x2="40" y2="80" />
          <line class="inner-line" x1="40" y1="80" x2="40" y2="120" />
        </g>
      </g>
    </svg>
  </div>

  
  <div class="controls">
    <button class="step-btn active" id="btn0" onclick="setStep(0)">1. Upside Down</button>
    <button class="step-btn" id="btn1" onclick="setStep(1)">2. Turn</button>
    <button class="step-btn" id="btn2" onclick="setStep(2)">3. Match!</button>
    <button class="play-btn" id="playToggle" onclick="togglePlay()" title="Play / Pause">⏸</button>
  </div>

  <script>
    const piece = document.getElementById('movingPiece');
    const stage = document.querySelector('.stage');
    const labelText = document.getElementById('labelText');
    const playToggle = document.getElementById('playToggle');
    const buttons = [
      document.getElementById('btn0'),
      document.getElementById('btn1'),
      document.getElementById('btn2')
    ];

    // Transformations for each step
    // Center of Target Slot is at x = 80 + 40 = 120, y = 40 + 60 = 100
    // Right starting position center is at x = 280, y = 100
    const steps = [
      {
        transform: 'translate(280px, 100px) rotate(180deg)',
        label: 'Turned Around',
        matched: false
      },
      {
        transform: 'translate(280px, 100px) rotate(0deg)',
        label: 'Turned to Match',
        matched: false
      },
      {
        transform: 'translate(120px, 100px) rotate(0deg)',
        label: 'Still Congruent! ✨',
        matched: true
      }
    ];

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

    function renderStep(index) {
      currentStep = index;
      const s = steps[index];

      // Apply transform & styles
      piece.style.transform = s.transform;
      labelText.textContent = s.label;

      if (s.matched) {
        stage.classList.add('matched');
      } else {
        stage.classList.remove('matched');
      }

      // Update button highlights
      buttons.forEach((btn, i) => {
        if (i === index) {
          btn.classList.add('active');
        } else {
          btn.classList.remove('active');
        }
      });
    }

    function setStep(index) {
      renderStep(index);
    }

    function nextStep() {
      const next = (currentStep + 1) % steps.length;
      renderStep(next);
    }

    function startAutoPlay() {
      if (timer) clearInterval(timer);
      timer = setInterval(nextStep, 2600);
      isPlaying = true;
      playToggle.textContent = '⏸';
    }

    function stopAutoPlay() {
      if (timer) clearInterval(timer);
      timer = null;
      isPlaying = false;
      playToggle.textContent = '▶';
    }

    function togglePlay() {
      if (isPlaying) {
        stopAutoPlay();
      } else {
        nextStep();
        startAutoPlay();
      }
    }

    // Initialize
    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">
  <title>Congruence Overlap Test</title>
  <style>
    * {
      box-sizing: border-box;
      margin: 0;
      padding: 0;
    }

    body {
      font-family: system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
      background: transparent;
      color: #0f172a;
      padding: 10px;
      display: flex;
      flex-direction: column;
      gap: 10px;
    }

    .header-bar {
      text-align: center;
      padding-bottom: 2px;
    }

    .header-bar h2 {
      font-size: 16px;
      font-weight: 700;
      color: #1e293b;
    }

    .header-bar p {
      font-size: 12px;
      color: #64748b;
      margin-top: 2px;
    }

    .test-card {
      background: #ffffff;
      border: 1.5px solid #e2e8f0;
      border-radius: 10px;
      padding: 10px 14px;
      display: flex;
      align-items: center;
      justify-content: space-between;
      gap: 12px;
    }

    /* Animation Stage */
    .stage-container {
      display: flex;
      flex-direction: column;
      align-items: center;
      gap: 4px;
    }

    .stage {
      position: relative;
      width: 180px;
      height: 82px;
      background: #f8fafc;
      border: 1px dashed #cbd5e1;
      border-radius: 8px;
      overflow: hidden;
      flex-shrink: 0;
    }

    .stage-label {
      font-size: 11px;
      font-weight: 600;
      color: #64748b;
    }

    /* Top Row - Shapes */
    .target-rect {
      position: absolute;
      left: 112px;
      top: 6px;
      width: 48px;
      height: 70px;
      background: #fef9c3;
      border: 2px solid #ca8a04;
      border-radius: 4px;
    }

    .moving-square {
      position: absolute;
      left: 14px;
      top: 17px;
      width: 48px;
      height: 48px;
      background: rgba(234, 179, 8, 0.88);
      border: 2px solid #a16207;
      border-radius: 4px;
      z-index: 2;
      animation: slideTop 3.5s ease-in-out infinite;
    }

    /* Mismatch highlight zones on target rectangle */
    .mismatch-zone {
      position: absolute;
      left: 112px;
      width: 48px;
      border: 2px dashed #dc2626;
      background: rgba(239, 68, 68, 0.25);
      border-radius: 3px;
      opacity: 0;
      animation: alertMismatch 3.5s ease-in-out infinite;
      z-index: 3;
      pointer-events: none;
    }
    .mismatch-top { top: 6px; height: 11px; border-bottom: none; }
    .mismatch-bottom { top: 65px; height: 11px; border-top: none; }

    /* Bottom Row - Triangles */
    .target-tri {
      position: absolute;
      left: 108px;
      top: 13px;
      width: 56px;
      height: 56px;
      animation: glowMatch 3.5s ease-in-out infinite;
      border-radius: 4px;
    }

    .moving-tri {
      position: absolute;
      left: 14px;
      top: 13px;
      width: 56px;
      height: 56px;
      z-index: 2;
      animation: slideBottom 3.5s ease-in-out infinite;
    }

    /* Result Badges and Information */
    .badge-col {
      display: flex;
      flex-direction: column;
      align-items: flex-start;
      justify-content: center;
      flex: 1;
      min-width: 120px;
      gap: 4px;
    }

    .badge {
      font-size: 13px;
      font-weight: 700;
      padding: 5px 10px;
      border-radius: 6px;
      display: inline-flex;
      align-items: center;
      gap: 5px;
      transition: opacity 0.3s ease;
    }

    .badge-desc {
      font-size: 11px;
      line-height: 1.3;
      color: #475569;
    }

    .badge-no {
      color: #991b1b;
      background: #fee2e2;
      border: 1.5px solid #ef4444;
      animation: highlightNo 3.5s ease-in-out infinite;
    }

    .badge-yes {
      color: #14532d;
      background: #dcfce7;
      border: 1.5px solid #22c55e;
      animation: highlightYes 3.5s ease-in-out infinite;
    }

    /* Synchronized 3.5s Animation Cycle */
    @keyframes slideTop {
      0%, 15%   { transform: translateX(0); }
      40%, 82%  { transform: translateX(98px); }
      95%, 100% { transform: translateX(0); }
    }

    @keyframes slideBottom {
      0%, 15%   { transform: translateX(0); }
      40%, 82%  { transform: translateX(94px); }
      95%, 100% { transform: translateX(0); }
    }

    @keyframes alertMismatch {
      0%, 38%   { opacity: 0; }
      44%, 82%  { opacity: 1; }
      90%, 100% { opacity: 0; }
    }

    @keyframes glowMatch {
      0%, 38%   { filter: drop-shadow(0 0 0px transparent); }
      44%, 82%  { filter: drop-shadow(0 0 7px #22c55e); }
      90%, 100% { filter: drop-shadow(0 0 0px transparent); }
    }

    @keyframes highlightNo {
      0%, 38%   { opacity: 0.45; }
      44%, 82%  { opacity: 1; }
      90%, 100% { opacity: 0.45; }
    }

    @keyframes highlightYes {
      0%, 38%   { opacity: 0.45; }
      44%, 82%  { opacity: 1; }
      90%, 100% { opacity: 0.45; }
    }

    /* Responsive adjustments for narrow widths */
    @media (max-width: 380px) {
      .test-card {
        padding: 8px 10px;
        gap: 8px;
      }
      .stage {
        width: 155px;
        height: 76px;
      }
      .target-rect {
        left: 96px;
        top: 5px;
        width: 44px;
        height: 64px;
      }
      .moving-square {
        left: 10px;
        top: 15px;
        width: 44px;
        height: 44px;
      }
      .mismatch-zone {
        left: 96px;
        width: 44px;
      }
      .mismatch-top { top: 5px; height: 10px; }
      .mismatch-bottom { top: 59px; height: 10px; }

      .target-tri {
        left: 94px;
        top: 12px;
        width: 50px;
        height: 50px;
      }
      .moving-tri {
        left: 10px;
        top: 12px;
        width: 50px;
        height: 50px;
      }

      @keyframes slideTop {
        0%, 15%   { transform: translateX(0); }
        40%, 82%  { transform: translateX(86px); }
        95%, 100% { transform: translateX(0); }
      }

      @keyframes slideBottom {
        0%, 15%   { transform: translateX(0); }
        40%, 82%  { transform: translateX(84px); }
        95%, 100% { transform: translateX(0); }
      }

      .badge {
        font-size: 12px;
        padding: 4px 8px;
      }
      .badge-desc {
        font-size: 10px;
      }
    }
  </style>
</head>
<body>

  <div class="header-bar">
    <h2>Overlap Test for Congruence</h2>
    <p>Congruent figures match perfectly in both size and shape.</p>
  </div>

  
  <div class="test-card">
    <div class="stage-container">
      <div class="stage" aria-label="Square sliding over a taller rectangle">
        <div class="moving-square" title="Square"></div>
        <div class="target-rect" title="Rectangle"></div>
        <div class="mismatch-zone mismatch-top"></div>
        <div class="mismatch-zone mismatch-bottom"></div>
      </div>
      <span class="stage-label">Square + Tall Rectangle</span>
    </div>
    <div class="badge-col">
      <div class="badge badge-no">✕ Not Congruent</div>
      <span class="badge-desc">Edges stick out — shapes do not match in size.</span>
    </div>
  </div>

  
  <div class="test-card">
    <div class="stage-container">
      <div class="stage" aria-label="Triangle sliding over an identical triangle">
        <svg class="moving-tri" viewBox="0 0 60 60" title="Moving Triangle">
          <polygon points="30,6 56,54 4,54" fill="rgba(34, 197, 94, 0.9)" stroke="#15803d" stroke-width="2.5" stroke-linejoin="round"/>
        </svg>
        <svg class="target-tri" viewBox="0 0 60 60" title="Target Triangle">
          <polygon points="30,6 56,54 4,54" fill="#bbf7d0" stroke="#16a34a" stroke-width="2.5" stroke-linejoin="round"/>
        </svg>
      </div>
      <span class="stage-label">Identical Triangles</span>
    </div>
    <div class="badge-col">
      <div class="badge badge-yes">✓ Congruent!</div>
      <span class="badge-desc">Fits perfectly — exactly the same size & shape.</span>
    </div>
  </div>

</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;
      user-select: none;
      -webkit-user-select: none;
    }

    body {
      font-family: system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
      background-color: #f8f9fa;
      color: #1e2945;
      display: flex;
      flex-direction: column;
      align-items: center;
      justify-content: center;
      min-height: 100%;
      padding: 16px;
    }

    .stage {
      position: relative;
      width: 100%;
      max-width: 440px;
      height: 220px;
      margin: 0 auto;
    }

    /* Star Slots */
    .star-slot {
      position: absolute;
      top: 45%;
      transform: translate(-50%, -50%);
      width: 110px;
      height: 110px;
      display: flex;
      flex-direction: column;
      align-items: center;
      justify-content: center;
    }

    .slot-a {
      left: 28%;
    }

    .slot-b-target {
      left: 72%;
    }

    .outline-guide {
      position: absolute;
      width: 100px;
      height: 100px;
      opacity: 0.25;
      stroke-dasharray: 4 4;
    }

    .star-svg {
      width: 100px;
      height: 100px;
      filter: drop-shadow(0 4px 6px rgba(0, 0, 0, 0.08));
      transition: filter 0.3s ease;
    }

    /* Moving Star B */
    #movingStarContainer {
      position: absolute;
      top: 45%;
      left: 72%;
      width: 110px;
      height: 110px;
      transform: translate(-50%, -50%);
      display: flex;
      flex-direction: column;
      align-items: center;
      justify-content: center;
      z-index: 10;
      pointer-events: none;
    }

    .label {
      font-size: 14px;
      font-weight: 700;
      color: #1e2945;
      margin-top: 6px;
      text-align: center;
      transition: opacity 0.3s ease;
    }

    /* Congruence Badge */
    .congruent-badge {
      position: absolute;
      top: 82%;
      left: 28%;
      transform: translate(-50%, -50%) scale(0.7);
      background: #16a34a;
      color: #ffffff;
      font-size: 13px;
      font-weight: 700;
      padding: 6px 12px;
      border-radius: 999px;
      display: flex;
      align-items: center;
      gap: 5px;
      box-shadow: 0 4px 12px rgba(22, 163, 74, 0.3);
      opacity: 0;
      pointer-events: none;
      z-index: 20;
      white-space: nowrap;
      transition: opacity 0.3s ease, transform 0.3s cubic-bezier(0.175, 0.885, 0.32, 1.275);
    }

    /* Active Matched State */
    .matched .star-svg {
      filter: drop-shadow(0 0 14px rgba(34, 197, 94, 0.85));
    }

    .matched .congruent-badge {
      opacity: 1;
      transform: translate(-50%, -50%) scale(1);
    }

    /* Controls */
    .controls {
      display: flex;
      align-items: center;
      justify-content: center;
      gap: 12px;
      width: 100%;
      max-width: 440px;
      margin-top: 4px;
    }

    .slider-wrap {
      flex: 1;
      display: flex;
      flex-direction: column;
      gap: 4px;
    }

    .slider-label {
      font-size: 12px;
      font-weight: 600;
      color: #6b7280;
      text-align: center;
    }

    input[type="range"] {
      width: 100%;
      height: 6px;
      accent-color: #0284c7;
      background: #e2e8f0;
      border-radius: 4px;
      outline: none;
      cursor: pointer;
    }

    .btn {
      background: #ffffff;
      border: 1px solid #cbd5e1;
      color: #1e2945;
      font-size: 14px;
      font-weight: 600;
      padding: 6px 14px;
      border-radius: 8px;
      cursor: pointer;
      display: inline-flex;
      align-items: center;
      gap: 4px;
      box-shadow: 0 1px 2px rgba(0,0,0,0.05);
    }

    .btn:active {
      background: #f1f5f9;
    }
  </style>
</head>
<body>

  <div class="stage" id="stage">
    
    <div class="star-slot slot-a" id="slotA">
      <svg class="star-svg" viewBox="0 0 100 100">
        <polygon points="50,5 64,36 98,36 70,57 81,91 50,70 19,91 30,57 2,36 36,36" 
                 fill="#00b4d8" stroke="#0077b6" stroke-width="3" stroke-linejoin="round" />
      </svg>
      <div class="label" id="labelA">Star A</div>
    </div>

    
    <div class="star-slot slot-b-target">
      <svg class="star-svg outline-guide" viewBox="0 0 100 100">
        <polygon points="50,5 64,36 98,36 70,57 81,91 50,70 19,91 30,57 2,36 36,36" 
                 fill="none" stroke="#64748b" stroke-width="2" stroke-linejoin="round" />
      </svg>
    </div>

    
    <div id="movingStarContainer">
      <svg class="star-svg" viewBox="0 0 100 100">
        <polygon points="50,5 64,36 98,36 70,57 81,91 50,70 19,91 30,57 2,36 36,36" 
                 fill="#00b4d8" stroke="#0077b6" stroke-width="3" stroke-linejoin="round" />
      </svg>
      <div class="label" id="labelB">Star B</div>
    </div>

    
    <div class="congruent-badge" id="badge">
      <span>✓</span> Congruent! Perfect Fit!
    </div>
  </div>

  
  <div class="controls">
    <button class="btn" id="playBtn" aria-label="Play or Pause">⏸ Pause</button>
    <div class="slider-wrap">
      <div class="slider-label">Slide to match</div>
      <input type="range" id="progressSlider" min="0" max="100" value="0">
    </div>
  </div>

  <script>
    const movingStar = document.getElementById('movingStarContainer');
    const labelB = document.getElementById('labelB');
    const stage = document.getElementById('stage');
    const playBtn = document.getElementById('playBtn');
    const slider = document.getElementById('progressSlider');

    const START_LEFT_PCT = 72;
    const END_LEFT_PCT = 28;
    const CYCLE_DURATION = 4000; // 4s loop

    let isPlaying = true;
    let startTime = performance.now();
    let currentProgress = 0;

    function setProgress(progress) {
      currentProgress = Math.max(0, Math.min(1, progress));
      slider.value = currentProgress * 100;

      // Position moving star
      const leftPos = START_LEFT_PCT - (currentProgress * (START_LEFT_PCT - END_LEFT_PCT));
      movingStar.style.left = leftPos + '%';

      // Visual state triggers
      if (currentProgress >= 0.96) {
        stage.classList.add('matched');
        labelB.style.opacity = '0';
      } else {
        stage.classList.remove('matched');
        labelB.style.opacity = '1';
      }
    }

    function animate(now) {
      if (isPlaying) {
        const elapsed = (now - startTime) % CYCLE_DURATION;
        const t = elapsed / CYCLE_DURATION;
        
        let p = 0;
        if (t < 0.2) {
          // Pause at start (0.8s)
          p = 0;
        } else if (t < 0.55) {
          // Smooth glide across (1.4s)
          const easeProgress = (t - 0.2) / 0.35;
          p = easeInOutCubic(easeProgress);
        } else if (t < 0.85) {
          // Hold aligned with glow badge (1.2s)
          p = 1;
        } else {
          // Reset glide back (0.6s)
          const returnProgress = (t - 0.85) / 0.15;
          p = 1 - easeInOutCubic(returnProgress);
        }

        setProgress(p);
      }
      requestAnimationFrame(animate);
    }

    function easeInOutCubic(t) {
      return t < 0.5 ? 4 * t * t * t : 1 - Math.pow(-2 * t + 2, 3) / 2;
    }

    // Play/Pause button
    playBtn.addEventListener('click', () => {
      isPlaying = !isPlaying;
      playBtn.innerHTML = isPlaying ? '⏸ Pause' : '▶ Play';
      if (isPlaying) {
        startTime = performance.now() - (currentProgress * 0.35 + 0.2) * CYCLE_DURATION;
      }
    });

    // Slider scrubbing
    slider.addEventListener('input', (e) => {
      if (isPlaying) {
        isPlaying = false;
        playBtn.innerHTML = '▶ Play';
      }
      setProgress(e.target.value / 100);
    });

    // Start loop
    requestAnimationFrame(animate);
  </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>The Congruence Test</title>
  <style>
    * {
      box-sizing: border-box;
      margin: 0;
      padding: 0;
      user-select: none;
      -webkit-user-select: none;
    }

    body {
      width: 100%;
      min-height: 100%;
      background: transparent;
      font-family: system-ui, -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
      color: #1e293b;
      display: flex;
      flex-direction: column;
      align-items: center;
      padding: 12px 8px;
    }

    .header {
      text-align: center;
      margin-bottom: 10px;
    }

    .title {
      font-size: 16px;
      font-weight: 700;
      color: #0f172a;
      letter-spacing: -0.01em;
    }

    .subtitle-badge {
      display: inline-flex;
      align-items: center;
      gap: 6px;
      margin-top: 4px;
      background: #f1f5f9;
      color: #475569;
      font-size: 11px;
      font-weight: 600;
      padding: 3px 10px;
      border-radius: 999px;
    }

    .hint {
      font-size: 11px;
      color: #64748b;
      margin-bottom: 10px;
      display: flex;
      align-items: center;
      gap: 4px;
    }

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

    .col {
      background: #ffffff;
      border-radius: 12px;
      padding: 8px 4px 10px 4px;
      display: flex;
      flex-direction: column;
      align-items: center;
      cursor: pointer;
      box-shadow: 0 1px 3px rgba(0,0,0,0.06), 0 1px 2px rgba(0,0,0,0.04);
      transition: transform 0.15s ease, box-shadow 0.15s ease;
      outline: 2px solid transparent;
      outline-offset: -2px;
    }

    .col:hover {
      box-shadow: 0 4px 8px rgba(0,0,0,0.08);
    }

    .col:active {
      transform: scale(0.985);
    }

    .col.active {
      outline-color: #94a3b8;
    }

    .col.active.match {
      outline-color: #10b981;
    }

    .canvas-box {
      width: 100%;
      height: 90px;
      display: flex;
      align-items: center;
      justify-content: center;
      position: relative;
    }

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

    .shape {
      transition: transform 0.5s cubic-bezier(0.4, 0, 0.2, 1);
    }

    .checklist {
      width: 90%;
      display: flex;
      flex-direction: column;
      gap: 4px;
      margin: 8px 0 10px 0;
    }

    .check-row {
      display: flex;
      justify-content: space-between;
      align-items: center;
      font-size: 11px;
      font-weight: 500;
      color: #475569;
      background: #f8fafc;
      padding: 3px 6px;
      border-radius: 4px;
    }

    .mark-pass {
      color: #16a34a;
      font-weight: 700;
      font-size: 12px;
    }

    .mark-fail {
      color: #dc2626;
      font-weight: 700;
      font-size: 12px;
    }

    .status-pill {
      font-size: 10px;
      font-weight: 700;
      text-transform: uppercase;
      letter-spacing: 0.02em;
      padding: 4px 8px;
      border-radius: 999px;
      text-align: center;
      white-space: nowrap;
    }

    .status-fail {
      background: #fee2e2;
      color: #b91c1c;
    }

    .status-pass {
      background: #d1fae5;
      color: #047857;
      border: 1px solid #10b981;
    }

    .action-prompt {
      font-size: 9px;
      color: #94a3b8;
      margin-top: 4px;
    }

    @media (max-width: 380px) {
      .title { font-size: 14px; }
      .check-row { font-size: 10px; padding: 2px 4px; }
      .status-pill { font-size: 9px; padding: 3px 6px; }
      .canvas-box { height: 75px; }
    }
  </style>
</head>
<body>

  <div class="header">
    <div class="title">The Congruence Test</div>
    <div class="subtitle-badge">
      <span>1. Same Shape?</span>
      <span>•</span>
      <span>2. Same Size?</span>
    </div>
  </div>

  <div class="hint">✦ Tap any pair to test overlap</div>

  <div class="grid">
    
    <div class="col" id="col1" onclick="togglePair(1)">
      <div class="canvas-box">
        <svg viewBox="0 0 120 90">
          
          <circle cx="34" cy="45" r="26" fill="rgba(239, 68, 68, 0.2)" stroke="#ef4444" stroke-width="2.5" stroke-dasharray="0" />
          
          <circle id="shape1" class="shape" cx="88" cy="45" r="14" fill="rgba(239, 68, 68, 0.5)" stroke="#dc2626" stroke-width="2.5" />
        </svg>
      </div>
      <div class="checklist">
        <div class="check-row"><span>Shape</span><span class="mark-pass">✓</span></div>
        <div class="check-row"><span>Size</span><span class="mark-fail">✕</span></div>
      </div>
      <div class="status-pill status-fail">Not Congruent</div>
      <div class="action-prompt" id="prompt1">Tap: Overlap</div>
    </div>

    
    <div class="col" id="col2" onclick="togglePair(2)">
      <div class="canvas-box">
        <svg viewBox="0 0 120 90">
          
          <rect x="13" y="24" width="42" height="42" rx="2" fill="rgba(245, 158, 11, 0.2)" stroke="#f59e0b" stroke-width="2.5" />
          
          <rect id="shape2" class="shape" x="78" y="18" width="22" height="54" rx="2" fill="rgba(245, 158, 11, 0.5)" stroke="#d97706" stroke-width="2.5" />
        </svg>
      </div>
      <div class="checklist">
        <div class="check-row"><span>Shape</span><span class="mark-fail">✕</span></div>
        <div class="check-row"><span>Size</span><span class="mark-fail">✕</span></div>
      </div>
      <div class="status-pill status-fail">Not Congruent</div>
      <div class="action-prompt" id="prompt2">Tap: Overlap</div>
    </div>

    
    <div class="col match" id="col3" onclick="togglePair(3)">
      <div class="canvas-box">
        <svg viewBox="0 0 120 90">
          
          <polygon points="34,22 11,66 57,66" fill="rgba(99, 102, 241, 0.2)" stroke="#6366f1" stroke-width="2.5" stroke-linejoin="round" />
          
          <polygon id="shape3" class="shape" points="86,22 63,66 109,66" fill="rgba(99, 102, 241, 0.55)" stroke="#4f46e5" stroke-width="2.5" stroke-linejoin="round" />
        </svg>
      </div>
      <div class="checklist">
        <div class="check-row"><span>Shape</span><span class="mark-pass">✓</span></div>
        <div class="check-row"><span>Size</span><span class="mark-pass">✓</span></div>
      </div>
      <div class="status-pill status-pass">✓ CONGRUENT!</div>
      <div class="action-prompt" id="prompt3">Tap: Overlap</div>
    </div>
  </div>

  <script>
    const states = { 1: false, 2: false, 3: false };
    const translations = {
      1: -54, // 88 - 34
      2: -55, // Center align rect over square: (13 + 21) - (78 + 11) = 34 - 89 = -55
      3: -52  // 86 - 34
    };

    function togglePair(num) {
      states[num] = !states[num];
      const shape = document.getElementById('shape' + num);
      const col = document.getElementById('col' + num);
      const prompt = document.getElementById('prompt' + num);

      if (states[num]) {
        shape.style.transform = `translateX(${translations[num]}px)`;
        col.classList.add('active');
        prompt.textContent = 'Tap: Reset';
      } else {
        shape.style.transform = 'translateX(0px)';
        col.classList.remove('active');
        prompt.textContent = 'Tap: Overlap';
      }
    }
  </script>
</body>
</html>

Spotting Symmetry in Nature and Daily Life

Folding Shapes to Find Matching Halves

Creating Symmetrical Paint Print Pictures

Using Mirrors to Explore Reflection

Completing the Other Half of a Symmetrical Picture

Building Symmetrical Designs with Blocks and Shapes

Creating Patterns With Objects

Distinguishing Symmetrical from Non-Symmetrical Shapes

math

Symmetry and Symmetrical Patterns

Sliding and Moving Shapes

Turning and Rotating Shapes

Flipping Shapes and Creating Mirror Images

Exploring Line Symmetry by Folding

Finding Symmetry with Mirrors and Nature

Exploring Scaling: Bigger and Smaller Same Shapes

Symmetry, Transformations, and Scaling

Understanding Scale Factors Greater Than One for Enlargement

Understanding Fractional Scale Factors for Reduction

Finding an Unknown Scale Factor from Original and Image

Enlarging and Reducing Shapes on a Square Grid

Enlarging Shapes Using a Center of Enlargement (Ray Method)

Reducing Shapes from a Given Center of Enlargement

Identifying the Center of Enlargement from Diagrams

How Scale Factor Affects Perimeter and Angle Conservation

Investigating the Effect of Scale Factor on Area

Using Digital Technology to Scale and Resize Graphics

Scale Factor, Enlargement, and Reduction

Understanding Scale Factors in Shape Enlargement

Enlarging Shapes on a Grid by Integer Scale Factors

Identifying Corresponding Sides and Angles in Enlargements

Calculating Scale Factors Between Similar Shapes

Enlarging Shapes from a Centre of Enlargement

Analysing How Perimeter Changes Under Enlargement

Analysing How Area Changes Under Enlargement

Fractional Scale Factors and Reductions

Solving Real-World Scale and Model Problems

Geometric Enlargements and Similar Shapes

Defining Similarity in Geometric Figures

Calculating Linear Scale Factors for Enlargement and Reduction

Finding Missing Side Lengths in Similar Triangles

Similar Triangles in Nested and Parallel Line Configurations

Similar Triangles in Crossing and Hourglass Configurations

Word Problems with Similar Triangles in Real Life

Similar Triangles and 2D Scale Factors

Translating Shapes on a Coordinate Plane Using Vectors

Reflecting Shapes Across the X-Axis and Y-Axis

Reflecting Shapes Across Diagonal Lines Like y = x

Rotating Shapes About the Origin by 90 and 180 Degrees

Transformations on the Coordinate Plane

Investigating the Relationship Between Length and Area Scale Factors

Calculating Enlarged and Reduced Areas Using k-Squared

Finding Linear Scale Factors from Area Ratios

Investigating the Relationship Between Length and Volume Scale Factors

Calculating Enlarged and Reduced Volumes Using k-Cubed

Finding Linear Scale Factors from Volume Ratios

Converting Between Area and Volume in Similar Objects

Solving Real-World Packaging, Model, and Material Scaling Problems

Area and Volume Scale Factors in Similar Figures

Understanding What Makes a Picture Symmetrical

Distinguishing Symmetrical From Non-Symmetrical Shapes

Finding Vertical Lines of Symmetry

Finding Horizontal Lines of Symmetry

Shapes With More Than One Line of Symmetry

Exploring and Finding Lines of Symmetry

Identifying All Lines of Symmetry in Triangles and Quadrilaterals

Lines of Symmetry in Regular and Irregular Polygons

Completing Symmetrical Shapes Across Slanted Mirror Lines

Completing Shapes with Two Intersecting Lines of Symmetry

Understanding Rotational Symmetry and Order of Rotation

Calculating the Angle of Rotation from the Order of Symmetry

Comparing Line Symmetry and Rotational Symmetry in 2D Shapes

Creating Rotational Symmetry Patterns on Grids and Pegboards

Creating Mandala and Tessellation Designs Using Symmetry

Line and Rotational Symmetry

Creating Symmetrical Paint-Print Pictures

Creating Symmetrical Paper Cutouts

Creating Symmetrical Pegboard Patterns

Checking Symmetry With Tracing Paper

Creating Symmetrical Art and Patterns

Understanding Grid Coordinates: (x, y) Ordered Pairs

Plotting and Reading Points in the First Quadrant

Drawing Polygons by Joining Coordinate Vertices in Quadrant One

Finding Missing Vertices of Rectangles and Squares on a Grid

Extending to Four Quadrants: Positive and Negative Axes

Plotting Coordinates with Negative Numbers in All Four Quadrants

Plotting and Classifying Shapes Across the Four Quadrants

Translating Shapes on a Coordinate Grid: Left, Right, Up, Down

Reflecting Shapes Across the X-Axis and Y-Axis on Grids

Plotting Points with Half-Unit and Decimal Coordinates

Coordinate Geometry Mystery Picture Challenges

The Coordinate System and Grid Navigation

Identifying Vertical, Horizontal, and Diagonal Lines of Symmetry

Finding All Lines of Symmetry in Regular Polygons

Testing Symmetry in Triangles and Quadrilaterals by Folding

Lines of Symmetry in Circles, Semicircles, and Ovals

Completing Symmetrical Figures Across a Vertical Mirror Line

Completing Symmetrical Figures Across a Horizontal Mirror Line

Completing Symmetrical Figures Across Diagonal Mirror Lines

Creating Symmetrical Patterns with Two Intersecting Mirror Lines

Designing Symmetrical Rangoli, Mandala, and Tartan Patterns

Identifying and Creating Tessellations with Symmetrical Tiles

Spotting and Correcting Asymmetry in Almost Symmetrical Drawings

Line Symmetry and Symmetrical Designs

Identifying Order of Rotational Symmetry in 2D Polygons

Calculating the Angle of Rotation from the Order of Rotational Symmetry

Comparing Line Symmetry and Rotational Symmetry in Geometric Shapes

Completing Patterns and Designs with Rotational Symmetry

Creating Mandala and Kaleidoscopic Designs with Rotational Symmetry

Investigating Rotational Symmetry in Rotational Tessellations

Spotting and Analyzing Rotational Symmetry in Nature and Architecture

Designing Corporate Logos and Emblems Using Symmetry Principles

Rotational Symmetry and Geometric Patterns

Exploring Physical Shape Movements: Slides, Flips, and Turns

Understanding Reflection as a Flip Across a Mirror Line

Reflecting Line Segments Across Grid Lines

Reflecting 2D Shapes Across Vertical and Horizontal Mirror Lines

Reflecting Shapes Across Diagonal Mirror Lines

Describing Reflections by Identifying the Mirror Line

Understanding Translation as a Slide on a Grid

Translating Points and Line Segments on Grids

Translating 2D Shapes on the Coordinate Plane

Using Column Vectors to Describe Translations

Invariance Properties in Reflections and Translations

Reflections, Translations, and Symmetry

Diferencias entre cuadrado y rectángulo

Tipos de triángulos por la longitud de sus lados

Composición de figuras complejas usando el tangram

Descomposición de polígonos en triángulos y cuadriláteros

Figuras congruentes: misma forma y mismo tamaño

Figuras semejantes: ampliación y reducción

Creación de diseños y mosaicos geométricos

Clasificación, composición y transformaciones de polígonos

Understanding Rotation: Angle, Direction, and Centre

Rotating Shapes 90 and 180 Degrees About a Vertex

Rotating Shapes About the Origin on a Coordinate Plane

Rotating Shapes About Arbitrary Centre Points

Identifying and Describing a Single Rotation

Performing Two-Step Transformations: Translation Then Reflection

Performing Two-Step Transformations: Reflection Then Rotation

Investigating Whether the Order of Transformations Matters

Creating Tessellations Using Translations and Rotations

Using Dynamic Geometry Software to Transform Shapes

Devising a Chain of Transformations to Solve Geometric Puzzles

Rotations and Combined Transformations

La simetría en la naturaleza y los objetos cotidianos

El eje de simetría en figuras planas

Completar figuras simétricas en papel cuadriculado

Figuras con más de un eje de simetría

Traslación de figuras en cuadrícula

Giros y rotaciones: un cuarto de vuelta y media vuelta

Giros en el sentido de las manecillas del reloj y en sentido contrario

Reconocimiento de congruencia tras movimientos rígidos

Creación de cenefas y patrones por traslación y reflexión

Transformaciones geométricas: simetría y giros

OGM.1.G.5

OGM.1.G.5

Aligned learning resources

Related diagrams