Sumerians used sharp to make symbols on clay tablets. (reeds/knives)

Reed, is the right answer.

Explanation:

A reed was a kind of pen made of reed straw and used by the Sumerians as a writing object. It was prepared by cutting and giving a shape of a pen. The evidence of reed pens dated back to 4th Century BC has been found from Ancient Egypt. These reed pens were generally used on papyrus and clay tablets to form written accounts.

there is no photo, therefore i can not answer your question.