The Diagonal Divorce

In 1924, Theo van Doesburg introduced diagonal lines into his work. Mondrian was furious. He considered diagonals a betrayal of the movement's principles and quit De Stijl over it. For Mondrian, only perfect horizontals and verticals expressed the fundamental forces of the universe — gravity and horizon, standing and lying.

His New York studio was itself a Mondrian painting. He taped colored rectangles to the white walls and rearranged them constantly. Visitors described entering the space as stepping inside one of his canvases. He lived his philosophy literally.