The traditional picture of an orderly series of scripts, each one invented suddenly and then completely displacing the previous one, has been conclusively demonstrated to be fiction by the archaeological finds and scholarly research of the later 20th and early 21st centuries. Gradual evolution and the coexistence of two or more scripts was more often the case. As early as the Shang dynasty, oracle-bone script coexisted as a simplified form alongside the normal script of bamboo books (preserved in typical bronze inscriptions), as well as the extra-elaborate pictorial forms (often clan emblems) found on many bronzes.