City and Port
The port manifests the border of the city, although the border of the videogame city is rarely seen. The potential endlessness of the city is eliminated when the avatar reaches the port. When the action moves onto a ship or something similar the city is expanded, it stretches out to engulf its surrounding aquatic activity. Some videogames make use of that. Others just offer the illusion of a sea opening, while it is in fact a gamespace design boundary, an uncrossable by the player threshold.
