What Were the Cones?

Decorated terra cotta cones are found at both Mohenjo-daro and Harappa, but no one knows what they may have been used for. Some scholars suggest that they were hung on a string as a plumb-bob for use by masons and carpenters. Others feel that they may have been toys or possibly used for writing. No traces of ink have been found on the tips, but many of the tips are worn smooth or chipped. What do you think they may have been used for?