Bus structure 2am-2pm is a three-dimensional model of the Sunday Minneapolis / St. Paul public transit system, where the horizontal axes represent directional movement and the vertical represents time. The piece is constructed of 47 horizontal layers, each forming a map of the bus routes that run during a given interval of time. Looking down from the top, one sees the Sunday bus map of the Twin Cities, while looking from the side, the times appears as strata building upwards. Within each layer, every transit route that operates at that time is represented by wood balls placed at its scheduled stops.