6 of at least 4 squares. (Just like Tian Zi)

There are at least 8 9 squares. (Just now, Tian Zi was equivalent to 1 line in a big mouth. 2 for each of the 9 squares)

16 plus 2, it becomes 10.

. . .

From 16 to 8 1, that is, the square of 4 to the square of 9, we need to add (9-4)*2= 10. That's twenty.