When the founder of the artmovement the Style: Theo van Doesburg, proposed to his partner in Style: Piet Mondriaan, the possibility of painting diagonal instead of straight lines, a fight broke out that ended their longtime friendship. Mondriaan kept on painting his straight rectangles for the rest of his life. Nonetheless he made a very peculiar move in his late paintings, when he flipped the square canvas on its point to create a diamond shape.