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