This is Edward de Bono’s original portrayal of a mental process which he in no way claims to have invented. In it he deliberately uses the lateral approach to sketch in the nature of lateral thinking.

          There emerges the concept of an imaginative, free-wheeling, opportunist mode of thought in which fresh ideas, which may well be simple, sound and effective, are often thrown up. Lateral thinking is thus contrasted with the orthodox, logical unimaginative process of vertical thinking, from which it differs as a bus differs from a tram. In a changing world both modes are required.