This is a classic puzzle game that was invented in the late 1870s in the USA. The goal of the game is to arrange 15 tiles inside the 4 by 4 square in the correct order with the empty square in the bottom right corner.You can do this by sliding the squares into the empty space. The final score is calculated, based on how quickly the puzzle is solved and also the aim of the game is to do the puzzle with the least amount of slides possible.Features:- automatic feature does not display unsolvable puzzle- You can change the digits,images and board skin (the colour or the font of the picture)- high scores are also a great feature of the game, compete with friends and other people. enjoy the game