Editing Marcel Duchamp (section)

==Kinetic works==
[[File:Marcel Duchamp, photo Man Ray, 391 n. 13, July 1920.jpg|thumb|Marcel Duchamp, 1918, ''A regarder d'un oeil, de près, pendant presque une heure, To Be Looked at (from the Other Side of the Glass) with One Eye, Close to, for Almost an Hour''. Photograph by Man Ray, published in [[391 (magazine)|391]], July 1920 (N13), [[Museum of Modern Art]], New York]]
Duchamp's interest in [[kinetic art]] works can be discerned as early as the notes for ''[[The Large Glass]]'' and the ''[[Bicycle Wheel]]'' readymade, and despite losing interest in "retinal art", he retained interest in visual phenomena. In 1920, with help from Man Ray, Duchamp built a motorized sculpture, ''Rotative plaques verre, optique de précision'' ("Rotary Glass Plates, Precision Optics"). The piece, which he did not consider to be art, involved a motor to spin pieces of rectangular glass on which were painted segments of a circle. When the apparatus spins, an optical illusion occurs, where the segments appear to be closed [[Concentric objects|concentric circles]]. Man Ray set up equipment to photograph the initial experiment, but when they turned the machine for the second time, a [[drive belt]] broke and caught a piece of the glass, which after glancing off Man Ray's head, shattered into bits.<ref name="TomkinsBio"/>{{rp|227–228}}

After moving back to Paris in 1923, at [[André Breton]]'s urging, with financing by [[Jacques Doucet (fashion designer)|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 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.<ref name="TomkinsBio"/>{{rp|254–255}}

''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 financial disaster, but some optical scientists thought they might be of use in restoring three-dimensional [[stereoscopic]] sight to people who have lost vision in one eye.<ref name="TomkinsBio"/>{{rp|301–303}} In collaboration with Man Ray and [[Marc Allégret]], Duchamp filmed early versions of the ''Rotoreliefs'', and they named the film ''[[Anémic Cinéma]]'' (1926). Later, in [[Alexander Calder]]'s studio in 1931, while looking at the sculptor's kinetic works, Duchamp suggested that these should be called ''[[Mobile (sculpture)|mobiles]]''. Calder agreed to use this novel term in his upcoming show. To this day, sculptures of this type are called "mobiles".<ref name="TomkinsBio"/>{{rp|294}}