The 15-puzzle (also called Gem Puzzle, Boss Puzzle, Game of Fifteen, Mystic Square and many others) is a sliding puzzle that consists of a frame of numbered square tiles in random order with one tile missing.Play all sizes, start from trivial 2x2 puzzles up to advanced 5x5 puzzles.The N-puzzle problem is a puzzle played on a N-by-N grid with N*N square blocks labeled 1 through (N-1) and a blank square. Your goal is to rearrange the blocks so that they are in order. 8-puzzle, 15-puzzle, Gem Puzzle, Boss Puzzle, Game of Fifteen, Mystic Square