In Greek art, the period ca. 1050–900 BCE. The decoration of pottery in this period was restricted to simple abstract elements such as horizontal bands, concentric circles and semicircles, and much of the surface of their of the pot was typically left undecorated (unlike in the style of the Geometric period that follows). Web resource here.

Protogeometric amphora from Athens. Ca. 975–950 BCE. British Museum, London. Photo: Marie-Lan Nguyen.