1. You have to take the pieces off and put it back together correctly.
Collect the pieces in this order:
Row 1: Left to right
Row 2: Left to right
Row 3: Left to right
Row 4: Left to right.
2. Now put the pieces back. Starting with the last piece you picked up, put it in the top left corner. Then the 2nd to last piece next to it, and so on in the same order you picked up the pieces. (marked in the picture above)