This is a set of plastic snap-together blocks that was designed for a prototype universal constructor. You can see a simulation of a robot made from the blocks here http://www.youtube.com/watch?v=LumLzSQE5VwYou can get more info on the strengths and weaknesses of the actual physical plastic blocks here http://www.molecularassembler.com/KSRM/3.18.htmThe parts were originally made using polyurethane casting. The files uploaded here have been modified to make them printer-friendly. But I haven't tested if they actually print...To make a part, you will need to print a top and a base. The top and base then have to be glued together. You can mix and match different tops and bases to make a variety of parts, including structural pieces, gears, racks, and so on.SnapBlocks.zip contains 16 stl files in dimensions of millimetersSnapBlocksAlibreSource.zip contains the source models in Alibre part format