How do you get 8? If you get 8, 12 should be easy.

1 square can be made by keeping two sides of the square along the axis.

Now another way to get the square with one vertex on the origin is to slant the square. If you slant the square it will form a right angled triangle with the axis where one side of the square is the hypotenuse of the triangle.

A right angled triangle with h=10 can have sides 6 and 8

So you can get a right angle triangle with (6,8) and another with (8,6).

Thus there are 3 possible squares that can be formed in one quadrant of the x-y plane. There are 4 planes... So 12 squares