This has got to by my favorite Nixie tube creation in a very long time – a fully-playable Soduku board.
Trashbear Labs built this Nixie Soduku board using 81 individual tubes, arranged into a grid, and controlled by a couple of dials and a keypad. There’s even a built-in solver algorithm, in case he gets stuck trying to solve a particularly challenging puzzle.
Want one just like it? Trashbear has been kind enough to share all of the schematics, source code, and design files in one handy .ZIP archive here.