If you think music repeats itself and that some songs sound
exactly the freaking same, there could be a reason for that
(well, other than piss poor artists being gobbled up by the
machine): there's a finite limitation on how different songs can
be. There is? Yep, says MATH.  The thinking is that there are a
finite number of tones our ears can distinguished and a few
notes in common in different songs can make the song sound
similar. So will we ever reach a point where every melody has
been recorded already? Watch the video and let math figure it
out for you. [YouTube]