The New York City subway, running all day and night, was the perfect emblem of this era. A sometimes breathtaking “wild style” graffiti had flourished in the system, but the same spray paint was also a marker of disorder, romanticized at a cost. Outside, the full-car murals were unforgettable and, in their way, influential in the worlds of painting and design; inside, the signage devolved into tags, mere scrawled names that hinted at the city’s inability to police even its own interiors.