Koh uses two-dimensional photography to create holographic, three-dimensional constructions. His photo sculpture has a transparent surface that reflects the images of the world, and yet reveals the emptiness of its interior space. The overlapping planes create an illusion of indefinable depth and varying imagery, depending on the viewing angle. Building 1990 is a box-shaped work that collages the photographic image of an abandoned building with a water image. The result is a surreal building whose windows are filled with blue seawater. The photograph was taken in New York in 1990.