James Turrell, Hover (two views), 1983.
From the Guggenheim:
Manipulating light as a sculptor would mold clay, James Turrell creates works that amplify perception. Unlike pictorial art that replicates visual experience through mimetic illusion, Turrell’s light works—one cannot call these shimmering events ”objects“ or ”images“—give form to perception. Each installation activates a heightened sensory awareness that promotes discovery: what seems to be a lustrous, suspended cube is actually the conjunction of two flat panels of projected light; a rectangle of radiant color hovering in front of a wall is really a deep, illuminated depression in the space; a velvety black square on the ceiling is, in reality, a portal to the night sky. With such effects, Turrell hopes to coax the viewer into a state of self-reflexivity in which one can see oneself seeing.
(via kojiroby)