Mark Rothko, No. 10,1950. Oil on canvas, 229.2 x 146.4 cm (90 1/4 x 57 5/8), The Museum of Modern Art, New York, Gift of Philip Johnson, 1952, © 1998, The Museum of Modern Art, New York

By 1950 Rothko had reduced the number of floating rectangles to two, three, or four and aligned them vertically against a colored ground, arriving at his signature style.