These two channels communicate with each other. The balloon and the little camera case are eager for traveling. Standing on and in between the platforms, you may observe the interaction between these black little things and passengers. Underground is a passage between the starting point and destination. That’s the process that everyone goes through either physically or psychologically. The artist tries to use the balloon to metaphor the moods of a person on his or her own journey, up and down, waiting and exciting. Sometimes, you even can’t move anywhere, and waiting all the time.