`The three panels of the rounded triptych ... indicate three domains of creativity which shade into each other without sharp boudaries: Humour, Discovery, and Art... Each horizontal line across the triptych stands for a pattern of creative activity which is represented on all three panels; ... The first is intended to make us laugh; the second to make us understand; the third to make us marvel.' (Koestler, The Act of Creation, p. 27).