This figure was taken by Matthew Marcus, and is reproduced with his permission. It was published in
W. F. Brinkman and P. E. Cladis, Physics Today 35, 48 (1982), (figure 7, page 53).
James P. Sethna, email@example.com
Statistical Mechanics: Entropy, Order Parameters, and Complexity, now available at Oxford University Press (USA, Europe).