At the end of my last post I talked about George Bell’s fascinating paper, “The Pennyhedron Revisited”, and a puzzle he mentions in it called “De Doe Dak Ka”. Stuart Gee designed it and George reports that it is the first known four-piece pennyhedron, having been introduced in 2007 at IPP27. It’s a very cool coordinate motion puzzle of four identical pieces. I started playing around with the shape, initially making a sphere and adding […]