Cool stuff and probably not a hoax, oscilloscopes are pretty much what you have in a crt tv but without the tuner(although in some older/cheaper ones you don't have much control over x other than the rate) so i was thinking it would just be some sort of analog out from a computer when it said it was done through the soundcard with the scope set to X-Y meaning you supply 2 input voltages, 1 for the x position of the beam and 1 for the y position, I've seen tv pictures on them before too.
