Classic puzzle right in Your hands.
Fifteen Puzzle - a puzzle, which is a 15 square tiles with applied numbers from 1 to 15. All the knuckles are enclosed in a square the size of 4x4 box (the box side of the square is four times longer than that of the knuckles). Thus when placing the tiles in one box remains empty space the size of a domino that can be used to move the tiles inside the box. The goal - to streamline the placement of the numbers in the box, placing them in ascending from left to right and top to bottom, starting with the knuckles with a number.