It is based on the slide puzzles. Where you have a square devided into 16 locations and one peice is removed allowing you to move 1 square into the vacant spot, creating a new vacant spot and so on. The cool thing with this puzzle is you can add your own graphics or photos. The screen shots shown are of my dog bingo. When Im traveling its kind of nice to pass the time putting his little face back together. I added some nice features like turning numbers on and off, Seeing the whole completed graphic at the touch of a button, just long enough to get your bearings, and the loading of any bmp file you have on the device. The number of moves are tracked at the top and it has online help, although I doubt you will need it.