I very usually put structure and form first, as a primary work that needs to be done. This is how I work in many cases.
In this case, the first thing that came to mind was the tetrachords. Then I started with the chords (the 2nd page, the slow part) and after I was done, I thought that I could actually repeat the same process at half time, and then half time again and again. So if you notice first the chords are in the woods, then the strings, and then there is a small mirrored 2 page part. This is repeated as a main process in the 2nd movement (the fast). First the woods have the theme, then the strings and then there is the mirror. 3rd movement (again slow) is pretty much the same things, at half speed. 4th 'movement' is the "resolution" sort of speak.
In order for the other "theme" to work it's way and meet with the form at the 4th 'movement' I went backwards and placed it in the last page, then half back and half back, etc until I reched bar 35, or something.
The number 4 did play a part in the whole thing. 4 movements,
tetrachords, 4 sections in each movements. But not much else really, no.
This is actually a very organised and guided piece. Once I got started I finished rather soon, because the form was repeating itself and I "had" to follow the structure. So once I got the idea of the chords, then the chrods in the strings, etc, next thing was already laid out. The "theme" of the 2nd "movement" (fast) is created by all possible variations of the 4 notes of the tetrachord. 1234, 3241, 1324, 1423, etc... Then it's a kind of fugato.
So my intuition as a composer is pretty absent. I didn't change anything after I was done and I do find this rather "wrong", as it is a work that could be presented even by a robot, or computer, with the minimum of input.
I think that I almost overanalysed this work!
