Dart Object 1951, cast 1962 Marcel Duchamp 1887-1968 Purchased with assistance from the National Lottery through the Heritage Lottery Fund 1997 http://www.tate.org.uk/art/work/T07280

Marcel Duchamp (b. 1887, France – d. 1968)
Objet-dard, 1951

It took me a while to decide what of Duchamp I should go with here.
It ended up being the Dart Object. The public answer is why not.

3 stoppages ?talon (3 Standard Stoppages) 1913-4, replica 1964 Marcel Duchamp 1887-1968 Purchased 1999 http://www.tate.org.uk/art/work/T07507

Marcel Duchamp (b. 1887, France – d. 1968)
3 stoppages étalon, 1913-14

Oh no, this one is even better.
Scientific methods for art making.
Such a lovely blurring of categories – by doing, not just by talking.