i was wondering about the "tv wall" thing i have seen in electronics stores, where a group of tvs will play seperate small images and then switch to one large image shown secton by section on the tvs. that description's not very good but hopefully you know what i'm talking about. well, my question is, how is this done? what sort of device is used, what is this "wall of tvs" effect actually called, is there a way i could do this for cheap? any information would be great. thanks!