Geometric abstraction is a form of abstract art based on the use of geometric forms sometimes, though not always, placed in non-illusionistic space and combined into non-objective (non-representational) compositions. Throughout 20th-century art historical discourse, critics and artists working within the reductive or pure strains of abstraction have often suggested that geometric abstraction represents the height of a non-objective art practice, which necessarily stresses or calls attention to the root plasticity and two-dimensionality of painting as an artistic medium. Thus, it has been suggested that geometric abstraction might function as a solution to problems concerning the need for modernist painting to reject the illusionistic practices of the past while addressing the inherently two dimensional nature of the picture plane as well as the canvas functioning as its support. Wassily Kandinsky, one of the forerunners of pure non-objective painting, was among the first modern artists to explore this geometric approach in his abstract work. Other examples of pioneer abstractionists such as Kasimir Malevich and Piet Mondrian have also embraced this approach towards abstract painting. Mondrian's painting Composition No. 10, 1939–1942, characterized by primary colors, white ground and black grid lines clearly defined his radical but classical approach to the rectangle.