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-68 is a building-shaped work featuring the photographic images of a building in Taipei. Different temporal and spatial traces coexist within the work. The photographs were taken over the course of four episodes in 2010.