In 1973, graffiti ran rampant in NYC, reaching its peak that summer. The work of black writers from the Bronx like SUPER COOL 223, RIFF 70 (WORM/CASH), and PHASE 2 defined the art which the kids called Top-to- Bottom or T-to-B, as it vertically covered a full subway car. Some T-to-B pieces were so elaborate and complex that the NYT hypothesized that they were a collaboration between professional artists and the graffiti writers. Here are photos from that heady era.