These are tiled geometry patterns in obj format, some of which would be troublesome to create by hand.

MORE IMPORTANTLY the download contains the C code that generated these geometry patterns and exports them to .obj  - potentially, a powerful tool.

Author's description:

This archive contains meshes of all of the regular and semi-regular tilings of the plane. Here a "regular" tiling is one consisting of only a single regular polygon. A "semi-regular" tiling may include more than one type of polygon, but every vertex will look identical. The archive includes:

• meshes of the three regular tilings
• meshes of the eight semi-regular tilings
• the C source used to generate these meshes

Each mesh contains roughly two thousand faces. The source can be used to generate tilings with more faces.

License 
As the sole author of this data, I hereby release it into the public domain.