This game is quite similar to Rubik's Cube, but is a lot easier. Basically you should finish the puzzle row by row.

For ease of presentation, the tiles are marked as follows:


You shouldn't have problems when finishing the first row:


To move tile 5 to its correct position, follow this procedure - move down, move left or right, then move up:


Follow the same procedure to move tile 6 to its correct position:


But you cannot follow the same procedure for tile 7, because tiles 5 and 6 will be disrupted if you do so. You need to modify the procedure slightly:


Follow similar steps to finish all rows until there is only one row left:


Swap the tiles in the last row until the puzzle is finished. Suppose you have arrived at the following situation:


You should swap tiles 15 and 16 first. Use the following formula:




Finally, use a similar trick to swap tiles 13 and 14.