The interior of a cube-shaped building. Openings in the five visible walls give views of three different landscapes. Though the topmost pair one looks down, almost vertically, onto the ground; the middle two are at eye-level and show horizon, while through the bottom pair one looks straight up to the stars.

Each plane of the building, which unites nadir, horizon and zenith, has a threefold function. For instance, the rear plane in the centre serves as a wall in relation to the horizon, a floor in connection with the view through the top opening and a ceiling so far as the view towards the starry sky is concerned.