Bird Wind (1955) by Peter Lanyon, San Francisco Museum of Art. Painted four years before Lanyon began gliding, one of Lanyon's first works to represent flight. It portrays a stall turn, in which a bird (or plane) climbs until its flight velocity drops to the point where it almost stalls. It then turns, falls and gathers speed until it is flying again and back in control. Lanyon to Patrick Heron: "just completed a flying orgasm".