sentences:  Rulers made from ivory were in use by the Indus Valley Civilization in what today is Pakistan, and in some parts of Western India prior to 1500 BCE.Excavations at Lothal dating to 2400 BCE have yielded one such ruler calibrated to about  Ian Whitelaw (2007) holds that 'The Mohenjo-Daro ruler is divided into units corresponding to and these are marked out in decimal subdivisions with remarkable accuracy—to within .Ancient bricks found throughout the region have dimensions that correspond to these units.'