Paint by number (or painting by numbers) are kits with a boar on which light blue lines indicate areas to paint, with each area having a number and a corresponding numbered paint to use. The kits were invented in 1950 by Dan Robbins who was employed by the Palmer Paint Company. The owner, Max S. Kline, asked Robbins for an idea for how to sell more paint. Robbins remembered being taught in high school that Leonardo da Vinci gave his assistants canvasses with numbered sections to paint. From this Robbins developed the kits.