Richard Tuttle, Perceived Obstacle No. 72 (Oil Painting #1), (1991), Oil and graphite on unstretched canvas, 13-3/4 x 38-1/2inches/34.9 x 97.8 cm, Photograph by Kerry Ryan McFate, courtesy Pace Gallery, Image © Richard Tuttle, courtesy Stuart Shave/Modern Art, London and Pace Gallery, New York