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<!DOCTYPE html>
<html>
<head>
  <meta charset="utf-8">
  <title>JS Alphabet Pattern 21 - Try It (Helper)</title>
</head>
<body>
  <h1>Diamond Alphabet &amp; Stars (Helper)</h1>
  <p>Edit n or the helper, then click Run.</p>
  <pre id="output" style="font-family: monospace; white-space: pre;"></pre>
  <script>
    function buildRow(i) {
      const ch = String.fromCharCode("A".charCodeAt(0) + i - 1);
      return Array(i).fill(ch).join("*");
    }

    const n = 5;
    let result = "";

    for (let i = 1; i <= n; i++) {
      result += buildRow(i) + "\n";
    }
    for (let i = n - 1; i >= 1; i--) {
      result += buildRow(i) + "\n";
    }

    document.getElementById("output").textContent = result;
  </script>
</body>
</html>

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JavaScript Alphabet Pattern 21 (Try It - Helper)