The Square was known to virtually all the ancient civilizations as a symbol of Earth, in contrast to the Circle, which represented heaven. (For
example, this was recorded by Chinese thousands of years ago, where the square was an emblem of the Chinese Emperors as lords of the earth, since the
earth was at that time perceived in Chinese cosmology to be square.)
In Freemasonry, the square and compasses (since compasses are used to draw circles) are symbolic of heaven and earth.
EDIT: That being said, if it was a square, the Egyptians most certainly would have got the angle of 90° right!
edit on 25/9/2012 by Saurus because: (no reason given)