A study of 150 stones dating back 1.4m years shows early humans were deliberately crafting spherical shapes – but nobody knows why. The Hebrew University of Jerusalem made findings after analysing the limestone balls which were unearthed in Ubeidiya, a dig site in Israel’s Jordan Rift Valley. Scientists have previously speculated that the stones, which were discovered in the 1960s and serve no discernable purpose, became round after being used as hammers. But the university’s team reconstructed the steps required to create the so-called spheroids and found they were part of a “preconceived goal to make a sphere”. The researchers used 3D analysis to retrace how they were made based on the markings and geometry of the spheroids. They concluded that the objects were intentionally “knapped”, the technique used to shape stone by hitting it with other objects. Antoine Muller, a researcher at the university’s Institute of Archaeology, said: “The main significance of the findings is that these spheroids from ‘Ubeidiya appear to be intentionally made, with the goal of achieving a sphere. “This suggests an appreciation of geometry and symmetry by hominins 1.4 million years ago.” Early humans clearly had some reason for making the balls, but what exactly that is remains a mystery. He said: “We still can’t be confident about what they were used for. A lot of work needs to be done to narrow down their functionality.” Sign up to our free Indy100 weekly newsletter Have your say in our news democracy. Click the upvote icon at the top of the page to help raise this article through the indy100 rankings.