Rectangular buildings became common from about 10,000 years ago, as seen in this reconstruction of the ancient city of atalhyk in Turkeyselimaksan/iStockphoto/Getty ImagesBuildings with corners have a much deeper history than we thought, adding an unexpected twist to a curious architectural mystery from the dawn of village life.Archaeologists have long been aware of a global trend in early architecture. From south-west Asia to the Americas, the very earliest settlements typically contained buildings with a round or oval-shaped ground plan. Then, usually a few thousand years later, these apparently went out of fashion, becoming