This is a variation of the classic 14-15 puzzle. On the early Mac, the 14-15 program was called PUZZLE. In early Windows, it was the only sample application for Microsoft Pascal for Windows 1.0, where it was called MUZZLE (for "Microsoft Puzzle"). This is the Xamarin.Forms version, so it's called Xuzzle, and the 15 tiles spell out the text "{XAMARIN.FORMS}".

If you open the solution in Xamarin Studio, it will not be able to load the Windows Phone project; and if you open the solution in Xamarin Studio under Windows, it will not be able to load the iOS project either.

After pressing the Randomize button, just tap a tile to move it into an empty position. You can tap any tile in the row or column of the empty position to move one, two, or three tiles at once. Use the numbers in the lower-right corner of each tile as a guide.

When you successfully complete the puzzle, you'll be rewarded with an animation.

Charles Petzold