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 some decorative grooves, almost like a bocce ball. Also, since the underlying shape is a rhombic dodecahedron, I also thought it might be interesting to split the rhombic faces into two triangles and then – well the pictures explain it better than I can:
Here they are in increasing stages of disassembly:
I like all the different symmetries these shapes exhibit and have enjoyed playing with them as fidget toys / dexterity puzzles. If you want to play with one of these yourself, I’m happy to report that Stuart Gee has very kindly given me permission to sell them. They are available at my Etsy store if you’re interested.