We crossed the room and walked up the access ramp to the station. A burst of feed advertising explained that the bubbles were a cup-shaped lift platform lined with padded benches, with a transparent bubble shield over the top so the humans couldn’t manage to fall out no matter how hard they tried. (The ad didn’t describe it that way.) The bubbles floated along a set path over the commercial segments and were much slower than the transit pipes, so they were mostly used for sightseeing. They also looked convenient for awkward conversations.