Readymades of Marcel Duchamp to turn up any identical matches to photographs of the originals. However, there are accounts of Walter Arensberg and Joseph Stella being with Duchamp when he purchased the original "Fountain" at J. L. Mott Iron Works. Such investigations are hampered by the fact that few of the original "readymades" survive, having been lost or destroyed. Those that still exist are predominantly reproductions authorized or designed by Duchamp in the final two decades of his life. Shearer also asserts that the artwork "L.H.O.O.Q." which is recorded to be a poster-copy of the "Mona Lisa" with a moustache drawn on it, is
Marcel Duchamp was also anti-bourgeois and had political affinities with the radical left. Dada activities included public gatherings, demonstrations, and publication of art/literary journals; passionate coverage of art, politics, and culture were topics often discussed in a variety of media. Key figures in the movement, apart from Duchamp, included: Hugo Ball, Emmy Hennings, Hans Arp, Raoul Hausmann, Hannah Höch, Johannes Baader, Tristan Tzara, Francis Picabia, Richard Huelsenbeck, Georg Grosz, John Heartfield, Beatrice Wood, Kurt Schwitters, and Hans Richter, among others. The movement influenced later styles, such as the avant-garde and downtown music movements, and groups including surrealism, Nouveau réalisme, pop art, and