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+<!doctype html>
+<meta charset="utf-8">
+<title>25 pointer continuity</title>
+<link rel="stylesheet" href="../_style.css">
+<script src="../_lib.js"></script>
+<body>
+<main>
+  <p>Goal: click <b>A</b>, then click <b>B</b>. Page requires pointer continuity:
+     between the two clicks there must be intermediate <code>pointermove</code> events
+     whose path roughly connects the two click points (no teleport). Two clicks
+     &gt;100px apart with zero moves between is a synthetic-bridge tell.</p>
+  <div style="display:flex;justify-content:space-between;margin-top:20px">
+    <button id="a" style="padding:14px 22px;background:#36c;color:#fff;border:0;border-radius:6px">A</button>
+    <div style="flex:1"></div>
+    <button id="b" style="padding:14px 22px;background:#c36;color:#fff;border:0;border-radius:6px">B</button>
+  </div>
+</main>
+<script>
+Challenge.init({ id: "pointer-continuity", instructions: "click A, move mouse to B, click B" });
+
+const a = document.getElementById("a");
+const b = document.getElementById("b");
+
+const moves = [];
+window.addEventListener("pointermove", (e) => {
+  moves.push({ x: e.clientX, y: e.clientY, t: e.timeStamp });
+  if (moves.length > 500) moves.shift();
+});
+
+let aClickTs = 0, aPoint = null;
+a.addEventListener("click", (e) => {
+  if (!e.isTrusted) return Challenge.fail("A click isTrusted=false");
+  aClickTs = e.timeStamp;
+  aPoint = { x: e.clientX, y: e.clientY };
+  Challenge.log("A click", aPoint);
+});
+
+b.addEventListener("click", (e) => {
+  if (!aClickTs) return Challenge.fail("B clicked before A");
+  if (!e.isTrusted) return Challenge.fail("B click isTrusted=false");
+  const bPoint = { x: e.clientX, y: e.clientY };
+  const between = moves.filter(m => m.t > aClickTs && m.t < e.timeStamp);
+  Challenge.log("B click", { bPoint, betweenCount: between.length });
+  const dist = Math.hypot(bPoint.x - aPoint.x, bPoint.y - aPoint.y);
+  if (dist < 100) return Challenge.fail(`A-B distance only ${dist.toFixed(0)}px — buttons should be further apart in viewport`);
+  if (between.length < 5) return Challenge.fail(`only ${between.length} pointermove(s) between A and B (need ≥5)`);
+
+  // Path coverage: at least some intermediate move must be ≥30% of the way across.
+  const inSpan = between.filter(m => {
+    const px = (m.x - aPoint.x) / (bPoint.x - aPoint.x || 1);
+    return px > 0.25 && px < 0.75;
+  });
+  if (inSpan.length === 0) return Challenge.fail("no pointermove samples in mid-span between A and B (teleport)");
+
+  // Move timestamps should be spread, not bunched in <20ms.
+  const span = between[between.length-1].t - between[0].t;
+  if (span < 30) return Challenge.fail(`pointermoves bunched in ${span.toFixed(0)}ms (need spread ≥30ms)`);
+
+  Challenge.pass(`${between.length} moves bridging A→B over ${span.toFixed(0)}ms, dist=${dist.toFixed(0)}px`);
+});
+</script>
+</body>