Bouncing balls in a heptagon · qwen3.5-35b-a3b

I need to build a 2D physics simulation with numbered balls inside a rotating heptagon. Let me create a complete, self-contained HTML file with:

1. A canvas element for rendering
2. CSS for styling
3. JavaScript for:
   - Physics simulation (gravity, collisions, friction)
   - Heptagon rotation
   - Ball rendering with numbers
   - Ball rotation (angular motion)
   - Pause/Resume and Reset functionality

Let me write this step by step:

```html
<!DOCTYPE html>
<html>
<head>
    <title>Heptagon Physics Simulation</title>
    <style>
        /* CSS for the canvas and controls */
    </style>
</head>
<body>
    <canvas id="canvas"></canvas>
    <div id="controls">
        <button id="pauseBtn">Pause</button>
        <button id="resetBtn">Reset</button>
    </div>
    <script>
        // JavaScript for the physics simulation
    </script>
</body>
</html>
```

I'll create a complete implementation with:
- 20 numbered balls with physics properties
- A rotating heptagon (7-sided polygon)
- Ball-to-ball collision detection
- Ball-to-wall collision detection with wall velocity
- Angular momentum and ball rotation
- Pause/Resume functionality
- Reset functionality

Let me write this to index.html.

Now let me open the file in the browser to verify the simulation works correctly.

There's a console error saying "heptagon is not defined" and the canvas appears empty. The file wasn't written correctly. Let me read the file and fix it.