To what extent is a piece of a piece a piece on its own? Do the movements connect as a sequence or a cluster or a network? Are the connections made from material identities or resemblances, or something less concrete, like style or character? Or are the connections more made from mirrors or negations?
(I've never been certain whether I like the word "movement", with its rather physical connotations, rather than the German, Satz ("setting"), with its own field of associations.)
My work-in-progress is in three movements: fast, slow, fast. So far, so conventional. And the material connections are everywhere obvious (these pitches, those rhythms, that texture, this tune), even if their application retains my patented obscurity. But for all that cheerful connectedness, it's bothersome that I can't quite get the tempi of the three movements to settle into some nice proportion, rather than let the second movement arbitrarily cut into the momentum of the first, and then the third into the second. I've probably spent more hours trying to get this to work out then it took to write every note in the piece, and there's still no end in sight. But I remain optimistic, and will persist, following some good counsel (Cummings):
in time's a noble mercy of proportion
with generosities beyond believing