 There is also anecdotal evidence the Sumerians may have used a type of slide rule in astronomical calculations.They were the first to find the area of a triangle and the volume of a cube.Discoveries of obsidian from far-away locations in Anatolia and lapis lazuli from Badakhshan in northeastern Afghanistan, beads from Dilmun (modern Bahrain), and several seals inscribed with the Indus Valley script suggest a remarkably wide-ranging network of ancient trade centered on the Persian Gulf.