Scholars consider cuneiform the first writing system, and humans used its wedge-shaped characters to inscribe ancient languages such as Sumerian on clay tablets beginning around 3400 BC.
Photograph of proto-cuneiform tablet showing signs discussed in the article. (Colour image of drawing of Fig. 4 in the article - Ref_ Englund 1994 ATU 5_ pl. 71).
Before Mesopotamian people invented writing, they used cylinder seals to press patterns into wet clay – and some of the symbols used were carried over into proto-writing ...