From Catherine Gillespie, Winmalee, New South Wales, Australia
In the report on ancient building shape, there was no mention of the critical relationship between the roofs and walls. The roof of a rectangular structure provides strength to ensure the walls stay upright. Such a roof requires strong structural elements and robust materials such as timber or stone before it can be clad with other things, such as thatch (8 March, p 14).
A circular structure may well be inherently stronger, thus requiring a simpler, less structural roof that uses easily available local resources, such as reeds or palm fronds or similar, which can also be easily replaced when damaged. This may explain why the evidence of early settlements has generally revealed round buildings.
