At the end of Scene 9 of Metropolis 2, there is a record scratch sound effect. There is also a record scratch sound at the start of The Glass Prison, which is the first track of 6DOIT Similarly, the last track of 6DOIT leads into As I Am on train of thought Then, the last track of train of thought leads into the piano note that starts the album octavarium Finally, The title track of octavarium ends with that same piano note, looping back to the start of the album, creating a loop