I saw this in the basement of the Whitney in May. The entire series is incredibly clever, and Mr. Nauman was ridiculously cute in his day.
One of my most favorite photos ever;
Bruce Nauman, Self Portrait as a Fountain
(Eleven Color Photographs)
(via » Go See – New York: “Photoconceptualism 1966-1973″ featuring works by Bruce Nauman, Dan Graham, Robert Smithson, Mel Bochner, Gordon Matta-Clark, Edward Ruscha Whitney Museum of American Art, through September 20, 2009 - AO Art Observed™)