Indus seals are small, flat squares carved from stone; each with an impression carved onto one side, and a knob protruding from the other. Most Indus Seals depict naturalistic animals and an as-yet untranslated script. The one-horned cow is a common animal featured on Indus Seals, sometimes portrayed next to an altar. Other animals include the elephant, rhinoceros, and tiger. Due to the fact that the language remains a mystery, the exact function of these seals is still unknown, though scholars think they were used to stamp clay as a method of keeping business and trade records.