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 globe cut in half, with black concentric circles painted on it. When it spins, the circles appear to move backward and forward in space. Duchamp asked that Doucet not exhibit the apparatus as art. "Rotoreliefs" were the next phase of Duchamp's spinning works. To make the optical "play toys", he painted designs on flat cardboard circles and spun them on a phonographic turntable. When spinning, the flat disks appeared three-dimensional. He had a printer produce 500 sets of six of the designs, and set up a booth at a 1935 Paris inventors' show to sell them. The venture was a