Over the course of three days, from February 14 to 16, 2007, Mel Bochner and his assistant Nicholas Knight installed Theory of Boundariesat the National Gallery of Art. The work, whose size is determined by the length of the wall on which it is installed, consists of four squares of equal size, each separated by a space equal to one-third of the width of a single square. Following the principles determined by the "language fraction" of each square (hence the work's title, Theory of Boundaries), dry pigment is applied directly to the wall, with each of the four squares demonstrating a different relationship of the color surface to its border and state of enclosure.