 This chord functions as a harmonic "frame" for the work in just the sense I meant earlier, in talking about all the events and details of a piece of music feel as if they belong together and constitute a convincing and unified musical continuity.Elsewhere he notes that this chord is "one of the two four-note groups that joins all the two-note intervals into pairs, thus allowing for the total range of interval qualities that still can be referred back to a basic chord-sound.This chord is not used at every moment in the work but occurs frequently enough, especially in important places, to function, I hope, as a formative factor."