(a) Both rectangular objects appear in contact with a wooden support surface, with the left object seeming to be farther away than the right object, (b) The actual configuration, in which both rectangular objects are the same distance from the camera in (a), and the left object is not in contact with the support surface. (Motivated by a similar demonstration in Gibson, 1950). Image from Thompson, Fleming, Creem-Regehr, & Stefanucci (2011). © 2011, CRC Press/An A. K. Peters Book, used by permission.