Hall Mirror
When you are walking down a hallway or corridor and someone coming the opposite way mirrors your every move to get out of each other's way. Often ends in a collision.
Sorry I was late to class, too many hall mirrors.
hall of mirrors
An error seen in 3-D videogames in which a certain spot fails to render, which makes the game simply re-render whatever was in view there last. The repeating image seen in place of what should be there is the Hall of Mirrors error.
Multiple Halls of Mirrors is usually a sure sign of a newbie mapper.