Even other artists' photographs. In the '80s, a mischievous cadre of self-styled rebels made "appropriation"—essentially, stealing—the point of their work. Sherrie Levine exhibited her own photographs of Walker Evans' famous Depression-era prints at a solo show in 1981 called "After Walker Evans." Depending on whom you ask, Levine was commenting on the nature of creativity or authenticity or gender or half a dozen other things. Perhaps she was demonstrating how copyright laws can be gamed for maximum absurdity. The Evans shots were in the public domain, so they could be copied with impunity, while Levine's knockoffs were "originals" and thus granted the full protection of law.

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