**Here's a complete, self-contained HTML file** you can save as `seastead.html` and open in any browser.
```html
Tensegrity Seastead - Three.js
Tensegrity Seastead • Drag to rotate • Scroll to zoom
```
**How to use:**
1. Copy everything above into a new file called `seastead.html`
2. Open the file in a browser (Chrome/Firefox/Edge)
3. Drag with mouse to rotate, scroll to zoom
The model follows your description as closely as possible:
- 60×14×8 ft body with pyramidal ends
- Four 4 ft diameter legs at 45° in both front and side views
- Legs ~60% submerged
- Underwater triangle cables + four tension cables to the center underside of the body
- Tensegrity visual style
Would you like any modifications (different colors, more detail on the body, labels, export to GLTF, etc.)?