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 much purer than art in its social position." On another occasion, Duchamp elaborated, "The chess pieces are the block alphabet which shapes thoughts; and these thoughts, although making a visual design on the chess-board, express their beauty abstractly, like a poem. ... I have come to the personal conclusion that while all artists are not chess players, all chess players are artists." In 1932, Duchamp teamed with chess theorist Vitaly Halberstadt to publish "L'opposition et cases conjuguées sont réconciliées" (Opposition and Sister Squares are Reconciled), known as corresponding squares. This treatise describes the Lasker-Reichhelm position, an extremely rare type of