From Robert Masta, Ann Arbor, Michigan, US
Many thanks for the Flint Dibble interview. It is no great surprise that multiple cultures would independently develop pyramids. We humans have a natural affinity for high places, probably dating back to spotting predators or enemies as well as a desire to be closer to the sky. (19 October, p 37)
A pyramid is a simple structure that can be built without the fancy lifting technology required for a tower, and can be made intrinsically stable. An ancient project engineer could demonstrate project feasibility to the ruling elite using a model comprehensible to any child.
