Self-contained painting kits that allow users to gradually reveal a pre-designed picture on a canvas or board by applying specific paint colors to the canvas's corresponding numbered sections. Often cheaply purchased at drug or art supply stores, these boxed sets became a popular leisure activity for middle-class Americans beginning in the early to mid-1950s. The original invention is credited to Dan Robbins and Max Klein of the Palmer Paint plant in Detriot, Michigan, who began marketing the kits in 1951. The inspiration for the invention is said to originate from Leonardo, who assigned numbered portions of his paintings to his apprentices for easy completion.
