They can also be one-way or two-way, teleporting players somewhere with no way to get back, or allowing them to teleport again." On the other hand, a 2009 paper by Alison Gazzard from the University of Hertfordshire provides some advantages of warps. Gazzard points that warps can be used to create puzzles and Easter eggs, saying that warps allow the player to "move through spaces in a way not possible in the real world, and discover ‘magical’ ways of traveling through the gamespace." Gazzard points out that warps make "travel from different parts of the game quicker" as well as act as a reward to allow to the player to access certain areas. Despite the linear simplicity of Super Mario Bros., the game has been described as having a "surprising amount of depth and spatial complexity" in part due to secret warp zones found through the game. Portal is a critically acclaimed game that uses warps as its core gameplay mechanic. See also Teleportation Teleportation in fiction Wraparound (video games) References Video game design Video game terminology