Intervallic expansion is one method composers use to transform their musical ideas. I think it creates the effect of familiarity at the same time of subtle difference. Sometimes they could be developmental in nature; sometimes they just happen over one fleeting moment you wonder if it's an isolated case / there's something special going on.

Speaking of intervallic expansion, perhaps there's another such example in the following music from section D. Ex. 3-2 is followed directly by Ex. 3-3.

Ex. 3-2 (low strings and low w.w.)
Ex. 3-3 (high strings and high w.w. enter)Can't really describe a particular "pattern" of intervallic expansion. Try these 2 ways of looking at it (hope I don't have any typo errors in the score, cos one little mistake could make a big difference).

1. Comparing last note of first group of notes with first note of red group of notes. Do this for first 2 bars of Ex. 3-2.

2. Comparing intervals within red group of notes.
In first 2 bars of Ex. 3-2: B#-C#-D-C# vs C#-D#-E#-E
In first 2 bars of Ex. 3-3: E-E#-F#-E vs E-G-A-G#

And probably compare with Ex. 3-1 too, the first time this "haunting" piece of tune is heard (see post on 10/9/2008).

I'm not sure what to make of this. All I can safely say is that they are familiar instances. They occur enough times in the piece to make you sit up and notice them. You know you've heard them before, but they do sound different, at the same time, you just can't easily put a finger on what's the difference. Perhaps in this way, it's better for me to speak in more generalised terms?