A general category for works (mainly vessels and sculptures) made from clay-based products hardened by heat. Ceramics represents an extraordinary range of specific materials, techniques, and styles dating from the earliest permanent human settlements, and the practice has distinct histories in all regions of the world. Broad sub-categories of ceramics include pottery, porcelain, and terracotta, each of which also have distinct histories across different regions and time periods. Notable early developments in ceramics include Cuneiform, the first known form of handwriting, which was produced on ceramic tablets in Mesopotamia as early as 3000 B.C; pottery spinning in ancient Egypt, China, and the Near East; and the invention of porcelain in China in the 7th or 8th century A.D. A broad cross-section of contemporary artists continue to push the technical and aesthetic boundaries of ceramics.