English: A circle within a square net, cutting exactly eight grid points at the side quarters of a 8 x 8 square (consisting of 64 units of area), seems to have diameter nearly 9. The circle may be inscribed in a greater square containing 16 more: an area of 80 units (given light yellow, by puzzling it from pieces of the two light grey squares). Therefore, the diameter of the circle must be less than 9 (accurately 4 times the square root of 5, i.e. about 8.944).