These are some simple models constructed with code and written to
the .x file format. You can view these models in the mesh view
utility that comes with the DirectX SDK.
A fractal decomposition of space known as the Menger Sponge
Spatial decomposition due to Ron Resch:
A simple temple constructed using D3DX shapes. This is a good
example of why modellers and artists should be used for games :-).