You know Picasso, right? In case you need a reminder, Picasso is a Spanish painter and sculptor who was one of the greatest and most influential artists of the 20th century (and all time). He co-founded Cubism, invented constructed sculpture, and co-invented collage. His most famous works are the 1907 Les Demoiselles d'Avignon and the 1937 Guernica. Kanye tweeted this famous Picasso quote â€” "Every child is an artist. The problem is staying an artist when you grow up."