From the link I posted:
"Let us look closely at two of the drawings on the sheet: we find a hexagram within a circle. If we were to place a smaller circle within the inner hexagon, that circle’s circumference would be exactly half of the outer circle. The hexagram itself contains the square and compass symbol of Freemasonry, which can be overlaid upon the image of the squared circle with the four tips of square and compass touching the outlying tips of the square. The other drawing is of an octagon. If we count the inner surfaces of the squared circle we come up with eight. In other words, the octagon is the perfect symbol of the actual image of the squaring of the circle."