1. A cheap strategy in tower defense type games in which the builder "walls off" the path of the monsters rather than putting them through a maze with a through path. This strategy is generally considered cheating and usually leads to being banned or otherwise punished.
2. On the highway, when there is exactly one car on every lane, the cars are all aligned with each other going at the same slow speed, and the cars maintain this position (usually unwittingly) without having been forced to by traffic or other reasons.
1. "Detected a wall in Player 2's tower maze; player 2 is now banned"
2. "Goddamn it those four drivers in front of me be walling and I can't fuckin pass them. There's no cars within 1000 feet of them; it's almost like it's coordinated."