20 x 20 = 400
18 x 18 = 324
16 x 16 = 256
14 x 14 = 196
12 x 12 = 144
10 x 10 = 100
8 x 8 = 64
6 x 6 = 36
4 x 4 = 16
2 x 2 = 4