Fifteen is a frustrating sliding puzzle that consists of a frame of 16 numbered square tiles in random order with one tile missing. By sliding tiles to the free square, the object is to put the tiles in order. It's a frustrating game as only half of the combinations are solvable. But it's addictive and amusing. It also keeps the brain running.

This version keeps track of speed (seconds to solve) and taps (the less the better).

Future versions will sync between your devices and an OS/X version