FifteenPuzzle can be purchased on Google Play
- Start by ordering the tiles on a corner or side of the frame
- When finally, there are 2 or 3 misplaced tiles left, try to group them into a square with the missing one by temporarily moving the surrounding well positioned tiles. Then rotate these misplaced ones so as to have them in their right position once all the moved tiles return to their once right position
- Always be guided by the left frame