Featured in the Bykert Gallery in New York in 1974, ​Mirrors of Light I ​consists of a spotlight directed at a diagonal row of mirrors; the resulting refractions form ellipses of varying size and proportion that are projected across the gallery walls. Holt was interested in using light as a medium, while simultaneously examining it as subject matter in its own right. In this single gallery setting, light is a conceptual entity and a physical reality, a practical resource and an aesthetic object.

Featured in the Walter Kelly Gallery in Chicago in 1974, ​Mirrors of Light II consists of a spotlight directed at a diagonal row of mirrors; the resulting refractions form ellipses of varying size and proportion that are projected across the gallery walls. Holt was interested in using light as a medium, while simultaneously examining it as subject matter in its own right. In this single gallery setting, light is a conceptual entity and a physical reality, a practical resource and an aesthetic object.

Holes of Light ​consists of a room bisected by a wall, which is perforated with eight circular holes arranged along a diagonal. Two lights are located on either side of the wall, and an alternating current switches between them so that one side of the room is dark and the other light. The projections of light are outlined on the walls so that the shapes are alluded to, even when they cannot be seen. The work generates a dynamic experience of the relationships between viewer and art object, practical and perceived, sensory and conceptual.