I’ve been having a lot of fun with coordinate motion puzzles, some of which I’ve even blogged about. Well, one of the coolest is a Stewart Coffin design (STC-112) called “Burr Muda” and it looks like this:
One of the things I really like about this design is that all six pieces are identical; that appeals to my sense of symmetry I suppose. Second, since it’s a coordinate motion puzzle, those six pieces must define a six-sided polyhedron. And indeed they do: the puzzle has a cube-shaped chamber at its center.
When I first came across pictures of Burr Muda, none of them showed it in its disassembled state so it took me a long time to figure out the shape of the fundamental piece. Even when I had calculated the correct shape I had the challenge of actually assembling the thing. Coordinate motion puzzles require that all the pieces be correctly aligned before they will slide together. With three piece puzzles, e.g., Viktor Genel’s ReCube, that’s not too much of a problem but Burr Muda has six. The solution was to make an assembly jig to hold some of the pieces in place during assembly:
The jig is handy for assembling the puzzle but I also like the way it shows off the internal structure of the puzzle and the interconnection of its six pieces.
Anyhow, I was so pleased with how it turned out that I thought it would make a great Exchange Puzzle for the IPP’s 39th gathering last August. Stewart generously gave me his permission to use his design and so I ended up making about ninety of them. I have about a dozen left over which I’m selling on my Etsy store.