For example, a fly might appear to be sitting on the painting's frame, or a curtain might appear to partly conceal the painting, a piece of paper might appear to be attached to a board, or a person might appear to be climbing out of the painting altogether—all in reference to the contest of Zeuxis and Parrhasius. In a 1964 seminar, the psychoanalyst and theorist Jacques Lacan (1901–1981) observed that the myth of the two painters reveals an interesting aspect of human cognition. While animals are attracted to superficial appearances, humans are enticed by the idea of things that are hidden.