记住正方形，然后打开它们
Remember squares and then open them.
Number of squares in levels:
1-10 levels - 16 squares. Must guess 4 squares.
11-20 levels - 25 squares. Must guess 5 squares.
21-30 levels - 36 squares. Must guess 6 squares.
31-all next levels - 49 squares. Must guess 7 squares.