From the earliest times, the illusions created by stage machinery offered a metaphor for the difference between appearance and reality. Plato in the The Republic [518c] uses the word periactoi translated as stage machinery in the description of his central idea of the soul turning from the darkness of the sensible world to the light of the Intelligibles. The periactoi on the Greek stage were probably paintings on a vertical spindle which could be revolved when the scene changed. Similarly Tesauro, in his lists of signs and events which have symbolic function from Il Cannochiale Aristotelico [Chapter 17] includes stage machinery. He justifies this by implying that these mechanisms are providing an illusion of reality. As he says, “theatrical apparatus and machinery are metaphors representing a place either real or imaginery by means of some appearance.” Pierre Coustau wrote an early emblem book Pegma a Latin word which can be translated as staging or theater, again implying the symbolic or illusionary nature of his text.