How many squares?

How many squares do you see?

1 + 16 + 2 + 8 + 4 + 4 + 1 + 4 = 40

1 is the large perimeter box that holds all the others.
16 are the obvious 4 rows of boxes in 4 lines.
2 are the inset boxes, which are dissected into another
8 smaller boxes. The 16 boxes also make
4 boxes that are 2x2 in each corner. Broaden that to
4 boxes that are 3x3 in each corner, along with
1 box in the center that is 2x2 and
4 more boxes that are 2x2 in the center of each side.
____

40 is the total.