Three separate tracks from the latest Tool album can be assembled into a different one -- it's like Voltron, only with progressive metal songs instead of progressive metal robots (seriously, those guys had a woman pilot before most airlines). But plenty of bands do multi-part songs, so there's nothing special about it, right?
Well, the difference is that, in this case, you don't get the full song by doing something as mundane as playing one track after the other -- you get it by changing the order and playing them at the same time.
By themselves, the songs seem completely different: "10,000 Days" (11:13) is a long prog-rock number, "Wings for Marie" (6:11) is a quiet song that builds up into a crescendo, and "Viginti Tres" (5:02) is just a bunch of weird noises. 6:11 plus 5:02 adds up to 11:13 -- that's because you're supposed to put "Viginti Tres" and "Wings for Marie" together (in that order) and play them at the same time as "10,000 Days."
If that sounds too complicated for you, check out the demonstration above. You'll notice that the weird sounds from "Viginti Tres" seem to be in sync with the melody of "10,000 Days."
The band has never acknowledged any of this, but if you listen to the full song it's pretty obvious that they did this intentionally ... which is both mind-blowingly awesome and a little bit insane.