[cripplecreek]

Here is an example of an illusion that does work in 3 dimensions. The room looks square but is likely a trapezoid with the perfect squares in the floor also being wildly distorted.

[Roccus]

When I was a teletypewriter repairman I swore some of the engineers at TTY Corp. were trying to incorporate my post #17 into the machines.

[Jack Hydrazine]

Maybe that’s how the Oregon Vortex height experiment works!
http://www.youtube.com/watch?v=1yC9FprP6UI