Mondrian's impressionist work is immaculate. If you ever have a chance to visit the Kunstmuseum in the Netherlands, go. But we're here for his mastery of abstraction. A practitioner of the De Stijl school of art theory, his signature pieces feature orthogonal grids of black on off-white canvases, with a handful of cells filled in primary colors. The whole language of the painting is a few right angles and three colors used sparingly.