The classic sliding block puzzle. The 15-puzzle consists of a 4-by ... When arbitrarily placing the 15 tiles into the box, attempts to solve the puzzle seemed to end up in one of two places: either ...

Have you ever been about to finish a puzzle, when suddenly you realize there are more holes left than you have pieces? With [Nikolaos’s] 3D printed sliding puzzles, this will be a problem of the ...