Look at the upper right corner first,/kloc-0 /×1+1= 2; 3×3+ 1= 10; 5×5+ 1=26; 7×7+ 1=50; 2→ 10→26→50→82→ 122→ 170; The increment of the difference is 8. Turn at the first turning; So the 25th corner is 170.

The lower right corner is 3→ 13→3 1→57, and the first difference is 10, 18, 26, 34; The second time is a single number, with a difference of 8. Make a second turn;

The lower left corner is 5 → 17 → 37 → 65, 1+ 1× 4 = 5, 5+3× 4 = 17, 17+4× 5 = 37, 37+4.

The first difference in the upper left corner is 1→7→2 1→43→73, the second difference is 6→ 14→22→30→38, and the second difference is the fourth corner. So the 20th angle is 73+38= 1 1 1.