Artists interested in abstraction are not concerned with accurately representing the visual world in their work. While some abstract artists distort the real world, other abstract artists are purely expressive and do not refer to the real world at all. Abstract art is sometimes referred to as nonrepresentational art. Piet Mondrian was a twentieth-century Dutch painter who pioneered abstraction in an art movement called De Stijl. Mondrian is famous for his paintings containing simple, balanced, geometric forms using a limited color palette.