'Nude Descending a Staircase No.2' 1912. Marcel Duchamp became much more famous for his Dada work and fabulous installations. Earlier however, he was a painter and had turned his unique eye to movement and how to capture it. Rendered in typical Cubist style drabs, for me, this doesn't have the powerful grace of Boccioni's sculpture (below), but it does give a feel for the tumbling lurch of everyday walking. I just looked at the Philadelphia Museum's entry for this painting, which they own. Amusingly, they list Duchamp as "American (born France)", and he did indeed become a US citizen, as did Greta Garbo and Stan Laurel. However, with all his work, you'd be hard to find a less American aesthetic. Incidentally, I was just about to add Einstein to that list of eminent European emigres of the mid 20th Century, but I seem to remember that he died stateless - by choice.