Assign a note to every number, then play Pi: The Music

Yes. Yes it is.

I think, if they had just used every note on the keyboard, it would sound chaotic. They probably tried a bunch of different keys (as in key signatures, as in, a specific selection of notes) and they've chosen to play this in D minor (?), presumably because it's the key that sounds the nicest.

It's played on the A Minor scale. But otherwise, what willfree said.

*raises hand*

*raises both hands*..Also without pi, that song wouldn't exist. So this post wouldn't possible w/o pi. Therefore your comment wouldn't exist. You need pi.