Puzzle 8 App For The iPhone and iPad
July 4, 2011

Have some free-time? Interested in AI programming? Then why not download one of our iPhone and iPad apps.

Free for a limited time — click here.

Don’t have an iPhone or iPad? Play the Java applet here.


The puzzle 8 – also known as the sliding-block puzzle or tile-puzzle – is one of the most popular instruments in the artificial intelligence (AI) studies. It belongs to AI exercises commonly referred as toy-problems.

Toy problems are devices that places constraints on larger real-world problems. They’re useful because they are simple to define and runs in a confined/controlled enviroment (the game board). It means that an exact description of the problems are possible, and all the factors that affects the problem are known (there is no need to worry about unpredictable factors such as weather or terrain). Such toy puzzles are perfect for software simulations. The 8-puzzle, along with chess, tic-tac-toe, backgammon, chess, and travelling salesman, have been used to study new search algorithms, neural-network, and path-finding. It’s usually one of the first instrument that computer-scientists use to test a new search algorithm.

This app implements the A* search (pronounced A-star) algorithm to find solutions. It may take a while for the applet to find a solution. If you become impatient, reshuffle and try another puzzle arrangement.