Minimis 2x2x1 puzzle cube

This is a 2x2x1 puzzle using just four pieces. Many designers use this puzzle as a starter project, but this one is unique in requiring only four pieces. No additional screws, pins, or other parts.

Several designers have inquired about this model since I uploaded it to Shapeways, so I'm posting the files here for the benefit of anyone who wants to learn from the source files.

If you can't build it yourself, you can buy it from Shapeways at http://www.shapeways.com/model/112492/minimis_2x