 Although the Greek term atomos is most commony associated with the solid and impenetrable bodies posited by Leucippus and Democritus, Plato’s Timaeus presents a different kind of physical theory based on indivisibles and was also regarded as a kind of atomism. Plato’s discussion of the composition of solids from plane surfaces is sometimes thought to be based on fourth-century Pythagorean theories. A fourth-century Pythagorean, Ecphantus, interpreted the Pythagorean monads as indivisible bodies: he is reported to have been sympathetic to atomism of a kind similar to Democritus’.