kind into music. In addition to Russolo, composers directly associated with this movement include the Italians Silvio Mix, Nuccio Fiorda, Franco Casavola, and Pannigi (whose 1922 Ballo meccanico included two motorcycles), and the Russians Artur Lourié, Mikhail Matyushin, and Nikolai Roslavets. Though few of the futurist works of these composers are performed today, the influence of futurism on the later development of 20th-century music was enormous. Sergei Prokofiev, Maurice Ravel, Igor Stravinsky, Arthur Honegger, George Antheil, Leo Ornstein, and Edgard Varèse are among the notable composers in the first half of the century who were influenced by futurism. Characteristic features of later 20th-century music with origins in futurism include the prepared piano, integral serialism, extended vocal techniques, graphic notation, improvisation, and minimalism. Free dissonance and experimentalism In the early part of the 20th century, Charles Ives integrated American and European traditions as well as vernacular and church styles, while using innovative techniques in his rhythm, harmony, and form. His technique included the use of polytonality, polyrhythm, tone clusters, aleatoric elements, and quarter tones. Edgard Varèse wrote highly dissonant pieces that utilized unusual sonorities and futuristic, scientific-sounding names. He pioneered the use of new instruments and electronic resources (see below). Expressionism By the late 1920s, though many composers continued to write in a vaguely expressionist manner, it was being supplanted by the more impersonal style of the German Neue Sachlichkeit and neoclassicism. Because expressionism, like any movement that had been stigmatized by the Nazis, gained a sympathetic reconsideration following World War II, expressionist music resurfaced in works by composers such as Hans Werner Henze, Pierre Boulez, Peter Maxwell Davies, Wolfgang Rihm, and Bernd Alois Zimmermann. Postmodern music Postmodernism is a reaction to modernism, but it can also be viewed as a response to a deep-seated shift in societal attitude. According to this latter view, postmodernism began when historic (as opposed to personal) optimism turned to pessimism, at the latest by 1930. John Cage is a prominent figure in 20th-century music, claimed with some justice both for modernism and postmodernism because the complex intersections between modernism and postmodernism are not reducible to simple schemata. His influence steadily grew during his lifetime. He often uses elements of chance: Imaginary Landscape No. 4 for 12 radio receivers, and Music of Changes for piano. Sonatas and Interludes (1946–48) is composed for a prepared piano: a normal piano whose timbre is dramatically altered by carefully placing