Ellsworth Kelly’s Green Panel (1980) depicts a trapezoid painted a bright green. The irregular shape reflects his interest in the dynamics of vision. “Roofs, walls, ceilings are all rectangles, but we don’t see them that way,” Kelly explains. “In reality they’re very elusive forms. The way the view through rungs of a chair changes when you move even the slightest bit — I want to capture some of that mystery in my work.”