[raymaniac]

If the picture is a manhole cover, than maybe the playing field will have two levels, one will be some thing like a street or sidewalk, and the other will be something like a sewer system, and the only way to get between the levels is through one of five manholes.
There could be five levels, but that is a lot less likely.
As for what the actual game will be, I don't know. It would be fun to do a sort of paintball or lasertag thing with a field like that.