I cannot claim to have any real understanding of what this phrase means, but I was wondering whether you all would agree with the meaning as it's put here:
The Pharaoh's stairway to the Heavens. This is a simulated view looking north. The pole star is in the center of all of the rings. Each band or layer of the pyramid represented five degrees of the dome of the sky (with the exception of the base layer due to other considerations). The circular pathways of the stars intersect with the pyramid as they rotate in the sky and become infused into the quadrangular tiers of the structure. This provides an insight into the esoteric meaning of 'squaring the circle': the circle is celestial and the square is terrestrial.

The picture that this is the caption for is the last one here:
http://www.crystalinks.com/steppyr.html
Thanks, Jo, for a very interesting site!