Here comes the train!
Actually, way back in the 50's, Ernie Kovacs did something similar. He had a skit called "Living Pictures", and he hung up a big picture of a tunnel and had a train come through, and a picture of a boat on the ocean and getting splashed by a wave. Just like Jim, Kovacs was really into exploring tv and seeing all the neat visual tricks he can conjure up. A lot of these were done live in front of an audience which makes them even more impressive.
But Jim's idea (with help from Jon Stone's direction, Joe Raposo's music, and Luis and Bob's great pantomime) worked great too. Shook me up as well.
Imagine if they did it in 3-D, wouldn't that be something?