The first 4 photos are examples of lever, used together to allow enable people to exercise better. The last photo shows a gas storage (I think it is for storage as the side says "(this part is unreadable) gas - do not tamper"). I have no idea why the gap is there in the first place, but there are a lot of cigarette butts on the gap. This encourages (in a way) people to continue smoking as it serves as an available place to throw their cigarette butts without being caught. More surprising, this is found outside a fast food restaurant. There should not be a gap there, in its place, join up the pipes.