Descending into a Washington, DC metro station is an arresting experience. A steeply inclined escalator inexorably carries passengers down, what feels like several stories, into the bowels of the earth through a large concrete tunnel. Visually, the experience is dominated by perspective. Every thing worth talking about is constructed of parallel lines, the wiring on the walls, the sequence of lights, the rubber belts that power the escalator. All these things converge at a single point, down beneath you. It simultaneously inspires vertigo and claustrophobia.