Kaleidocycles.

By Miss Cellania in Gadgets, Hacks & Mods, Toys on Apr 16, 2007 at 7:33 am

A kaleidocycle is a three-dimensional object made up of at least six regular tetrahedra in a way that can be joined to show a series of connecting faces. At M.C. Escher Kaleidocycles, you’ll see different kinds of kaleidocycles and instructions for making your own. Link -via Ursi’s Blog.