Left: Carmen Herrera, Equation, 1958, acrylic on canvas, 24 x 42 inches, Collection of Stanley Stairs and Leslie Powell, New York. Image courtesy Lisson Gallery, © Estate of Carmen Herrera

Right: Leon Polk Smith, Okie, 1957, oil on canvas, diameter: 31 1⁄4 inches, Leon Polk Smith Foundation. Image courtesy Lisson Gallery, photo: Mark Waldhauser, © Leon Polk Smith Foundation