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Peering inside clay balls
Credit: Anna Ressman/Courtesy Oriental Institute of the University of Chicago.
Scientists are using CT Scans and 3D modelling to peer inside sealed clay balls, often called "envelopes" by researchers. Only about 150 intact examples survive worldwide today and they contain, within them, tokens in a variety of geometric shapes. Their purpose was to record economic transactions but how exactly they did this, before writing was invented, is unknown. The examples the team scanned were excavated from the site of Choga Mish, in western Iran, in the late 1960s and are now at the University of Chicago's Oriental Institute. They date back about 5,500 years, roughly two centuries before the invention of writing. The exterior of each ball contains an "equatorial" seal running down the middle and, often, two polar seals running above and below.