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 circle. When the apparatus spins, an optical illusion occurs, where the segments appear to be closed concentric circles. Man Ray set up equipment to photograph the initial experiment, but when they turned the machine for the second time, a belt broke, and caught a piece of the glass, which after glancing off Man Ray's head, shattered into bits. After moving back to Paris in 1923, at André Breton's urging, with financing by Jacques Doucet, Duchamp built another optical device based on the first one, "Rotative Demisphère, optique de précision" (Rotary Demisphere, Precision Optics). This time the optical element was a