And the invention of transformations of certain figures has become the most important in musical composition.

Since I started composing I have always worked with series of tempos, even superimposed the music of different groups of musicians, of singers, instrumentalists who play and sing in different tempos simultaneously and then meet every now and then in the same tempo.

No, what is important is neither linearity or non-linearity, but the change, the degree of change from something that doesn't move to other events with different tempos in particular.

Karlheinz Stockhausen Quotes