Kaleidocycles are a mechanical toy featuring a number of tetrehedra chained together to form a loop which can be rotated in on itself. They were popularised and named by Wallace Walker in the 1950s; and have continued to show up in media and museum gift shops ever since.
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A tessellation is a set of figures which can cover the plane indefinitely. A hinged tessellation is a set of figures which not only cover the plane indefinitely, but has a set of hinges such that each figure can rotate about …
The other evening while playing Scrabble I was thinking about the biggest word one could actually play. Obviously 8 letter words come up often, and coming up with 9 letter examples are also quite straight forward. Given that a Scrabble board is 15x15, clearly the challenge would be finding 15 …