The already classic scene in which Paul wrenches the chorus to Get Back out of himself shows us, not just a moment of inspiration, but how the group pick up on what is not an obviously promising fragment and begin the process of turning it into a song. In the days to follow, they keep going at it, day after day, run-through after run-through, chipping away, laboriously sculpting the song into something that seems, in its final form, perfectly effortless. As viewers, we get bored of seeing the...