# Over the top

I was having fun browsing the 3D Printing marketplace Shapeways, and then I stumbled across this $17 \times 17 \times 17$ Rubik’s Cube by Oskar van Deventer and my brain exploded a little bit.

Van Deventer has designed an impressive collection of cube-like puzzles which can only be made by 3D printing.

I have an older puzzle by him called Topsy Turvy mounted on the wall in my office. This one isn’t 3D printed, but it requires lasers to carefully etch the paths so that the numbered coins can stack perfectly until the very end, and then cascade to make a particular permutation. To me it is not interesting as a puzzle at all (and frankly neither is the $17^3$ cube), but I like Topsy Turvy as mathematical art, and especially as a “faithful embedding” of the Mathieu group M12 in physical space.