Abstract art based on Cézanne's idea that all depiction of nature can be reduced to three solids: cube, sphere and cone. With the painting "Les Demoiselles d'Avignon" (1907), Picasso dramatically created a new and radical picture depicting a raw and primitive brothel scene with five prostitutes, violently painted women, reminiscent of African tribal masks and his own new Cubist inventions. Analytic cubism was jointly developed by Pablo Picasso and Georges Braque, from about 1908 through 1912. Analytic cubism, the first clear manifestation of cubism, was followed by Synthetic cubism, practiced by Braque, Picasso, Fernand Léger, Juan Gris, Albert Gleizes, Marcel Duchamp and
Pablo Picasso exposure to French painting. The generally upbeat and optimistic mood of paintings in this period is reminiscent of the 1899–1901 period (i.e. just prior to the Blue Period) and 1904 can be considered a transition year between the two periods. By 1905, Picasso became a favourite of American art collectors Leo and Gertrude Stein. Their older brother Michael Stein and his wife Sarah also became collectors of his work. Picasso painted portraits of both Gertrude Stein and her nephew Allan Stein. Gertrude Stein became Picasso's principal patron, acquiring his drawings and paintings and exhibiting them in her informal "Salon" at