Why did the Egyptians change from the rectangle shape of their early mastaba-type tombs to a square base for their pyramids?
   Sam, Web post

Dr. dig responds:
The rectangular shape of the mastaba tomb developed naturally from the oblong pit-graves used during the predynastic period. A rectangular base, however, would not give a symmetrical pyramid, and symmetry was considered important as the symmetrical pyramid was both better looking and structurally safer. One puzzle is Djoser's Step Pyramid at Sakkara, which started life as an unusual square mastaba, and ended up as the only Egyptian pyramid with a rectangular ground plan.