I wanted to write something that used the full range of trombone sounds. Not “range” in terms of high and low notes, but in terms of the full assortment of sounds available to the trombone.
Beside the normal sound from lips vibrating in the mouthpiece, I used mouth pops, streams of air blown into the mouthpiece without buzzing, clicking the mechanical parts of the horn, playing short puffs of sound, and hitting the bell with a soft mallet (no dents to show for it!).
Sequence that into a groove and you have a complex trombone sound that might have been played by Spock after finishing a rousing game of 3-D chess.