<!DOCTYPE html>
<html lang="ja">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>効率的な数学的パターン - Canvas API</title>
    <style>
        body { margin: 0; display: flex; justify-content: center; align-items: center; height: 100vh; background: #f0f0f0; }
        #controls { position: absolute; top: 10px; left: 10px; }
    </style>
</head>
<body>
    <div id="controls">
        <button id="redraw">再描画</button>
   