Level 1 - Press the square 2nd to the end. Now press first row 3rd square. Now press the 1st square.
Level 2 - Press the one on the second row 2nd to the last. Then the 1st row 4th square. Then 2nd row 2nd square.
Level 3 - Press the 2nd row 1st square. Then the 4th row 4th square, then the last row, last square.
Level 4 - Press the 3rd row 3rd square. Then 2nd row 3rd square. Then 1st row 3rd square.