[4] The Sixth Symphony is distinguished from its predecessors by a canzona-like structure, with an exceptionally high level of invention.
Motivic development is carried out in series of extended sections each with a distinct texture, steadily increasing in speed through to the end of the second movement.
The reversion in the finale to the lento tempo of the opening movement is accomplished more rapidly, with the correspondence becoming exact only close to the end.
[2] The symphony opens with an hallucinatory, otherworldly texture that sounds like music only just in the process of being formed—music without rhythm, melody, or harmony.
This is created using only nine instruments: three flutes, three trumpets, and three solo strings, in superimposed rhythmic layers that divide the slow beat into nine, ten, and twelve subdivisions simultaneously.