<P> Stone knapping with limited digital dexterity makes the center of gravity the required direction of flake removal . Physics then dictates a circular or oval end pattern, similar to the handaxe, for a leftover core after flake production . This would explain the abundance, wide distribution, proximity to source, consistent shape, and lack of actual use, of these artifacts . </P> <P> Mimi Lam, a researcher from the University of British Columbia, has suggested that Acheulean hand - axes became "the first commodity: A marketable good or service that has value and is used as an item for exchange ." </P> <P> The geographic distribution of Acheulean tools--and thus the peoples who made them--is often interpreted as being the result of palaeo - climatic and ecological factors, such as glaciation and the desertification of the Sahara Desert . </P> <P> Acheulean stone tools have been found across the continent of Africa, save for the dense rainforest around the River Congo which is not thought to have been colonized by hominids until later . It is thought that from Africa their use spread north and east to Asia: from Anatolia, through the Arabian Peninsula, across modern day Iran and Pakistan, and into India, and beyond . In Europe their users reached the Pannonian Basin and the western Mediterranean regions, modern day France, the Low Countries, western Germany, and southern and central Britain . Areas further north did not see human occupation until much later, due to glaciation . In Athirampakkam at Chennai in Tamil Nadu the Acheulean age started at 1.51 mya and it is also prior than North India and Europe . </P>

According to the current fossil record acheulean technology