“The Pennyhedron Revisited” Revisited

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 […]

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Mo’ CoMo

I continue to be intrigued (obsessed?) with coordinate motion (como) puzzles and came across a really clever design of James Dalgety’s. He is one of the living legends in the puzzle design community and is well known for having started Pentangle Puzzles & Games in 1971 and more recently for curating the Puzzle Museum, an immense collection of puzzles dating back to 320 BC. Here is a paper he submitted to the 11th “Gathering for […]

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ReCube ReVisited

Last February I blogged about Viktor Genel’s “ReCube” puzzle and the fun I had making cubical and spherical versions of it. Then, last August, I got to talking to George Bell about coordinate motion puzzles generally and about ReCube in particular. After some emails back and forth on how to model the spherical version in OpenSCAD, I realized I had omitted an internal vertex and the faces it anchors. I hate it when that happens. […]

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Stewart Coffin’s “Burr Muda” Puzzle

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 […]

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Coordinate Motion

Or is it “Coordinated Motion”? The latter makes more sense but the former seems to be the accepted term for describing burr-like puzzles whose assembly requires two or more pieces to be moved simultaneously and continuously. I guess I’ll just go with the flow and call them “coordinate motion puzzles.” One of the most beautifully made puzzles I’ve ever come across, coordinate motion or otherwise, is the machined aluminum / joined wood / metal 3D […]

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