In the movie there seemed to be 6 eras where events happened. I say eras because it started at some point from the past and unwrapped to the future. So these 6 eras seemed to be consecutive.
But then it occurred to me (forgive me I can't remember the names) that the Cloud-Atlas symphony was made by the composer after he had a dream he had been in a 'futuristic cafe' where he heard it. So he composed it. But if these eras where consecutive then he couldn't have had the dream hearing his own song since he hadn't composed it yet. So is it possible that these events were parallel, and kinda happening at the same time? Because if he hadn't composed it the cafe wouldn't play it and so he couldn't have the dream that helped him compose the Cloud-Atlas symphony, it's a circle. Hope I'm clear enough