Let me provide a corrected version with more precise measurements and transformations to create a proper octahedron:
```html
3D Octahedron
```
The key changes in this version:
1. Adjusted the perspective and scene size for better visibility
2. Used more accurate geometric calculations for the triangles
3. Centered the faces using transform-origin and translations
4. Set proper angles for top (30°) and bottom (210°) pyramids
5. Made the triangles larger and more proportional
6. Simplified the transforms to reduce distortion
The octahedron should now appear as a proper 3D shape with 8 triangular faces meeting at 6 vertices. Let me know if you'd like any adjustments to the appearance or animation.