Apologies if this has been discussed to death already.
In Valley of Darkness (S02E02) Starbuck and Helo break into Starbuck's Caprica apartment and she plays music that her father composed for her- the music that plays though is one of Phillip Glass' most popular and enduring pieces Metamorphosis One.
On the surface it seems like they've just used it in the place of some music Kara's dad made for her and for years there was a couple of years there was no reason to think otherwise.
Then the end of Crossroads II (S03E20), which shows people hearing Bob Dylan's All Along the Watchtower mysteriously, reveals that those who are hearing it are the Final Five cylons. Not only does it reveal the

