T.Cuyler Young/Royal Ontario Museum

A still later development involved dispensing with the actual tokens and creating a numeral system; now inventories were incised on clay tablets, and objects were recorded with the use of numbers along with a sign denoting the object. The sign for a large measure of grain, the sphere, was used to refer to “10” and the sign for a small measure of grain, the cone, was used to refer to “1.” This 3100 B.C. tablet, from Godin Tepe in Iran, is inscribed with signs for 44 objects (four spheres and four cones, which in two dimensions appear as circles and triangles).