A short review of Keith Sonnier's solo exhibition at the Castelli Warehouse in New York.The reviewer categorizes Sonnier's mixed media work into two distinct tendencies, the geometrical and the theatrical. Although he notes a lot of weak work, the reviewer commends he metaphorical structuring of Sonnier's work, focused as it is on the problem of structuring light, via projection, emanation, transparency, and reflection. The reviewer concludes that the technological elements of Sonnier's work are unfortunately cumbersome, a problem he considers typical of a new media that has yet to be fully integrated into art practice.