But her bike is there, on B-2, behind a column of nicked concrete. “Back off,” it says when she’s five feet away. Not loud, like a car, but it sounds like it means it. Under its coat of spray-on imitation rust and an artful bandaging of silver duct-tape, the geometry of the paper-cored, carbon-wrapped frame makes Chevette’s thighs tremble. She slips her left hand through the recognition-loop behind the seat.