The Cubist emphasized a flat, two-dimensional surface and rejected the idea that art should imitate nature, refusing traditional techniques such as perspective, foreshortening, modeling, and chiaroscuro (A word borrowed from Italian ("light and shade" or "dark") referring to the modeling of volume by depicting light and shade by contrasting them boldly.). The paintings are not supposed to look real. Spanish painter, Pablo Picasso and French artist Georges Braques in Paris founded the movement before World War I. The movement is considered to have its roots in the work of Post-Impressionist, Paul Cezanne. It also took from African tribal art, reducing everything to cubes and other geometrical forms. Cubist artists depicted drastically fragmented objects, sometimes showing multiple sides simultaneously. Cubism was the forerunner of abstract art.