in this example, a set of three pitches multiplied with a set of two pitches gives a new set of 3 × 2 pitches. given the limited space of modulo 12 arithmetic, when using this procedure very often duplicate tones are produced, which are generally omitted. this technique was used most famously in boulez's 1955 "le marteau sans maître", as well as in his third piano sonata, "structures ii", "don" and "tombeau" from "pli selon pli", "eclat" (and "eclat multiples"), "figures-doubles-prisms", "domaines", and "cummings ist der dichter", as well as the withdrawn choral work, "oubli signal lapidé" (1952) (; ; ). this operation, unlike arithmetic multiplication and transpositional combination of set classes, is non-commutative .