An invisible wall is a boundary in a video game that limits where a player character can go in a certain area, but does not appear as a physical obstacle.[1] The term can also refer to an obstacle that in reality could easily be bypassed, such as a mid-sized rock or short fence, which does not allow the character to jump over it within the context of the game.[2] In 2D games, the edge of the screen itself can form an invisible wall, since a player character may be prevented from traveling off the edge of the screen. [citation needed]