To consider whether tragedy is fully developed by now in all its various species or not, and to criticize it both in itself and in relation to the stage, that is another question. At any rate it originated in improvisation—both tragedy itself and comedy. The one came from the prelude to the dithyramb and the other from the prelude to the phallic songs which still survive as institutions in many cities. Tragedy then gradually evolved as men developed each element that came to light and after going through many changes, it stopped when it had found its own natural form. Thus it was Aeschylus who first raised the number of the actors from one to two. He also curtailed the chorus and gave the dialogue the leading part. Three actors and scene-painting Sophocles introduced.
– Aristotle Poetics 1449a
In Aatt enen tionon choreographed by Boris Charmatz in 1996, three dancers perform separately on a three-level stage. The stage can be erected in any suitably sized space, inside or outside. The audience organize themselves informally around the tripled-decked stage, like ancient Greeks in a landscape (artificial or natural). But the orkestra on which the dancers perform has been split in such a way that none can see the other two; there can be no coordination of the dance.
– Simon Unwin The Ten Most Influential Buildings in History: Architecture’s Archetypes