In the wake of excitement among the Unity community after the announcement of popular video game portal, I created a prototype of a working "portal gun". In Portal, the player is given a device with which they can position two portals on certain walls and other surfaces. When both are put in place, the form a sort of inter-dimensional gate through which the player and other objects can pass. For example, the player might shoot a hole in the wall, and then the ceiling, and then walk through the wall, falling out the ceiling immediately afterward. I mimicked this behavior in a small demo as an experiment. When I gave out the source code others in the community tried to make it into a community project, however, that did not succeed.

Image from wired.com