 Coe published a series of books offering pictures and interpretations of unknown Maya vases, with the Popol Vuh Twin myth for an explanatory model.In 1981, Robicsek and Hales added an inventory and classification of Maya vases painted in codex style, thereby revealing even more of a hitherto barely known spiritual world.As to subsequent developments, important issues in Schele's iconographic work have been elaborated by Karl Taube.