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 Mirror by TheStig1214 March 3, 2011

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.

hall of mirrors by Nimbostratus February 10, 2005