When Gilliam decided to dispense with the painting stretcher, it was a pretty revolutionary decision. Artists have applied paint to board, stretched canvas and other taut supports for centuries. Gilliam was applying paint to a piece of canvas but taking that canvas and putting it out in the world as a three-dimensional object, one whose shape would alter with every installation. Light Depth (1969) is a 10-by-75-foot length of canvas. Gilliam knotted it in five places, creating baroque swags of color. One of the swags is cinched up with a string, breaking its sweep. The work's installation, usually across a corner, is different each time, but the soaked tie-dye-like colors retain something of the '60s zeitgeist. (Kelly Klaasmeyer)