On either side of the bridge, a small robot hangs suspended by two wires. As a pedestrian walks below, eyes focused on the digital map in hand, the servos in the metal disk whir. The wires spool and unspool, moving the metal disk. It positions itself accordingly, hovering over the position of he bridge on the large map decal on the bridge's glass wall. As the pedestrian continues down the street, the robot on the wall follows, leaving a red line on the glass, a trace of the day's movement.
Inside the bridge, with laptop bag in hand, an office worker shuffles to the other side, incidentally stepping on a green floor tile. Outside, with the speed of a magician's trick, the robot's path starts laying down a green line instead. Catching the sudden change, the worker pauses, and turns back, making sure to intentionally step on a yellow tile. Once again, the color changes.