Home : Tune Toys : Expresso
Expresso takes a simple musical expression (literally "X") and mutates it. In each generation, transformations are applied to components of the expression. This is a fractal technique known as an L-system. The more generations there are, the larger and more complex the expression gets (and the longer it can take to compute). The output varies wildly, from boring to fascinating. Press "Mutate" a few times till you get something that looks interesting, then click on the image to play it. See Composer's Quarry for examples of output.

Transformations:
 Seed: Randomize seed: Generations: 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 Phrase for X: Basic 1 - c,e,gBasic 2 - c,g,e,b-Basic 3 - c,gBasic 4 - cBasic 5 - co3,co4,co3,co2Chord 1 - c e gChord 2 - c e- gChord 3 - c e- g b-Chord 4 - c f gFile 1 - bachinv1.midFile 2 - bachinv2.midFile 3 - bachinv3.midFile 4 - bachinv4.midFile 5 - bachinv5.midFile 6 - bachinv6.midFile 7 - bachinv7.midFile 8 - bachinv8.mid # of Tracks: 1234 Randomize patches: noyes Results may not appear for a few seconds.Be patient!
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 After 20 generations the expression "X" became this: (transpose((transpose((transpose((((((((step(((X+transpose(X,4) ) +transpose(X,7) ) ,12) +transpose(transpose(echo(X,4,6) ,4) ,4) ) +transpose(arpeggio(echo(X,4,6) ) ,7) ) +echo((echo(X,4,6) +transpose((X+transpose(X,7) ) ,12) ) ,4,6) ) +shuffle(((transpose(echo(X,4,6) ,4) |transpose(X,-7) ) +transpose(shuffle(arpeggio(transpose(X,4) ) ) ,7) ) ) ) +transpose((echo(transpose(step(step(transpose(((X+transpose(X,12) ) +transpose(X,7) ) ,-7) ,12) ,12) ,-7) ,4,6) +transpose(transpose((echo(transpose((X+transpose(X,12) ) ,-7) ,4,6) +transpose(step(arpeggio(X) ,12) ,12) ) ,-7) ,7) ) ,12) ) +transpose(shuffle(((transpose(((((((X+((X+transpose(X,12) ) +transpose(echo(X,4,6) ,12) ) ) +transpose(transpose(step(X,12) ,-7) ,4) ) +transpose((((transpose(X,-7) |X) +transpose(((X+transpose(X,7) ) +transpose((X+transpose(X,12) ) ,12) ) ,4) ) +transpose((echo(X,4,6) +(X+transpose(X,12) ) ) ,7) ) ,7) ) +transpose(((X+transpose(X,7) ) +transpose(((transpose(X,4) +transpose(echo(X,4,6) ,12) ) |step(transpose(X,4) ,12) ) ,7) ) ,4) ) +transpose(arpeggio((X+transpose(X,12) ) ) ,7) ) |step((((transpose(((X+transpose(X,4) ) +transpose(X,7) ) ,-5) +echo(X,4,6) ) +transpose(transpose(transpose(step(X,12) ,-7) ,-7) ,4) ) +transpose((transpose(echo(X,4,6) ,-7) +shuffle(X) ) ,7) ) ,12) ) ,-5) +transpose(step(echo(shuffle(transpose((((X+transpose(X,4) ) +transpose(X,7) ) +transpose((X|echo(X,4,6) ) ,7) ) ,4) ) ,4,6) ,12) ,7) ) |arpeggio(shuffle(step(transpose(X,4) ,12) ) ) ) ) ,4) ) +transpose((arpeggio(arpeggio((transpose((X+transpose(X,7) ) ,4) +transpose(transpose(step(X,12) ,4) ,12) ) ) ) |((shuffle(((step(shuffle(X) ,12) +transpose((X+transpose(X,12) ) ,4) ) +transpose(((X+X) +transpose(arpeggio(X) ,12) ) ,7) ) ) +transpose(((transpose(X,-5) |shuffle((echo(((X+transpose(X,4) ) +transpose(X,7) ) ,4,6) +transpose(step((X+transpose(X,12) ) ,12) ,12) ) ) ) +transpose(shuffle(((step(shuffle(X) ,12) +transpose((((transpose(X,4) +transpose(X,4) ) +transpose(X,7) ) +(X|X) ) ,4) ) +transpose(step(X,12) ,7) ) ) ,12) ) ,4) ) +transpose(arpeggio(((((X+transpose(X,12) ) +transpose((X+transpose(X,7) ) ,4) ) +transpose(arpeggio(X) ,7) ) +transpose((((X+transpose(X,4) ) +transpose(X,7) ) |X) ,12) ) ) ,7) ) ) ,7) ) ,4) +transpose((echo(((step((arpeggio(transpose((X|X) ,4) ) +transpose(shuffle(echo(((X|X) +transpose((X+transpose((X+transpose(X,12) ) ,7) ) ,7) ) ,4,6) ) ,12) ) ,12) +transpose(((shuffle(((transpose(X,-5) +transpose((echo(X,4,6) |X) ,4) ) +transpose(echo(X,4,6) ,7) ) ) +transpose(transpose(step((step(((step(X,12) +(X+transpose(X,12) ) ) +transpose((shuffle(X) |echo(X,4,6) ) ,12) ) ,12) +transpose(transpose(arpeggio(echo(X,4,6) ) ,-5) ,7) ) ,12) ,-5) ,4) ) +transpose(transpose((echo(transpose(transpose((X+transpose(X,12) ) ,4) ,-5) ,4,6) +(shuffle(arpeggio(X) ) +transpose(((arpeggio(X) +transpose(((X+transpose(echo(X,4,6) ,4) ) +transpose(((X+transpose(X,4) ) +transpose(X,7) ) ,7) ) ,12) ) +transpose(shuffle(X) ,12) ) ,12) ) ) ,-7) ,7) ) ,4) ) +transpose((((echo(shuffle((echo((X+transpose(X,12) ) ,4,6) +transpose((X+step(X,12) ) ,7) ) ) ,4,6) +((arpeggio(X) |(X+transpose(X,7) ) ) +transpose((((((X+transpose(X,7) ) +transpose(X,12) ) +transpose(X,4) ) +transpose(shuffle((X+X) ) ,7) ) +shuffle((X|X) ) ) ,7) ) ) +transpose(((X|((X+transpose(X,4) ) +transpose(X,7) ) ) +transpose((echo(X,4,6) |(X+transpose(X,7) ) ) ,12) ) ,4) ) +transpose(((step(transpose(echo((X+transpose(X,7) ) ,4,6) ,4) ,12) +transpose(((echo(X,4,6) +transpose(step(step(X,12) ,12) ,4) ) +transpose(((X+transpose(X,12) ) +transpose(echo(X,4,6) ,12) ) ,7) ) ,4) ) +transpose(((transpose(transpose(X,4) ,4) |(step(arpeggio(X) ,12) +transpose((X+(X|X) ) ,7) ) ) +transpose((arpeggio(step(arpeggio(X) ,12) ) +transpose((((X+transpose(shuffle(X) ,12) ) +transpose((transpose(X,-7) +transpose(((X+transpose(X,4) ) +transpose(X,7) ) ,7) ) ,4) ) +transpose(shuffle(arpeggio(X) ) ,7) ) ,12) ) ,12) ) ,7) ) ,7) ) ,7) ) ,4,6) +((transpose((shuffle((((X+transpose(X,4) ) +transpose(X,7) ) +transpose(X,7) ) ) +transpose(X,7) ) ,-7) +transpose(step((((transpose(((X+transpose(X,7) ) +arpeggio(X) ) ,-5) |step(X,12) ) +transpose(step(arpeggio(X) ,12) ,12) ) +transpose(transpose(transpose((step(X,12) +transpose(shuffle(X) ,12) ) ,-7) ,-7) ,7) ) ,12) ,4) ) +transpose(((shuffle(transpose((X+transpose(X,7) ) ,-7) ) +transpose(arpeggio(((echo(arpeggio(step(X,12) ) ,4,6) +transpose((((step(X,12) +transpose(X,7) ) +transpose(transpose(((X|X) +transpose((X+transpose(X,12) ) ,12) ) ,4) ,12) ) +transpose(transpose(arpeggio((shuffle(X) +transpose(X,12) ) ) ,-5) ,12) ) ,4) ) +transpose(transpose(arpeggio(echo(transpose((X+transpose(X,12) ) ,-5) ,4,6) ) ,4) ,7) ) ) ,12) ) +transpose(step((arpeggio(X) +transpose(((X+transpose(X,12) ) +transpose(arpeggio((X+X) ) ,12) ) ,7) ) ,12) ,7) ) ,7) ) ) ,12) ) ,4) +transpose(transpose(transpose(((((shuffle(transpose((((X+X) +transpose((X+transpose(step(X,12) ,7) ) ,4) ) +transpose((X|X) ,7) ) ,4) ) +shuffle(shuffle((X+transpose(((((transpose(X,-5) +transpose(X,12) ) +transpose((X+transpose(X,12) ) ,4) ) +transpose(shuffle(arpeggio(X) ) ,7) ) +transpose(((X+transpose(echo(X,4,6) ,4) ) +transpose(echo(X,4,6) ,7) ) ,12) ) ,7) ) ) ) ) +transpose(((shuffle(X) |transpose((((transpose(X,-7) +transpose(X,4) ) +transpose(step(X,12) ,7) ) +transpose(arpeggio(X) ,12) ) ,-7) ) +transpose((((transpose((echo(X,4,6) |shuffle(X) ) ,-7) +transpose(transpose(step((X+transpose(((X+transpose(X,4) ) +transpose(X,7) ) ,12) ) ,12) ,-7) ,4) ) +transpose(step(((arpeggio((X+transpose((X|X) ,7) ) ) +transpose((echo(X,4,6) +transpose(X,12) ) ,4) ) +transpose((shuffle(X) +transpose(X,12) ) ,7) ) ,12) ,7) ) +transpose(((step(transpose(echo(shuffle(X) ,4,6) ,-7) ,12) |((transpose(shuffle(X) ,-5) |(X+transpose(X,12) ) ) +transpose((X+transpose(X,7) ) ,12) ) ) |shuffle(arpeggio(X) ) ) ,7) ) ,7) ) ,7) ) +transpose((((shuffle(shuffle(step(X,12) ) ) |(((step(X,12) +transpose(step(X,12) ,7) ) +transpose(step((transpose(X,4) |step(transpose(X,-5) ,12) ) ,12) ,12) ) +transpose(shuffle(X) ,7) ) ) +transpose((((((arpeggio(X) +transpose((X|X) ,7) ) +transpose(shuffle((shuffle(X) +transpose(echo(X,4,6) ,12) ) ) ,7) ) +transpose(echo(((echo(echo((X+transpose(X,12) ) ,4,6) ,4,6) +transpose(((((X+transpose(X,4) ) +transpose(X,7) ) +transpose(((X|X) +transpose(X,12) ) ,4) ) +transpose(echo(((X+transpose(X,4) ) +transpose(X,7) ) ,4,6) ,7) ) ,4) ) +transpose(arpeggio(X) ,7) ) ,4,6) ,12) ) +transpose(arpeggio(transpose(echo(echo(transpose(X,-7) ,4,6) ,4,6) ,-7) ) ,4) ) +transpose(((((shuffle(X) +transpose((X+X) ,12) ) +((transpose(X,4) |arpeggio(X) ) +transpose(shuffle(X) ,7) ) ) +transpose(((X+transpose(X,12) ) +transpose(transpose(X,-5) ,12) ) ,4) ) +transpose(echo(transpose(X,-5) ,4,6) ,7) ) ,7) ) ,7) ) +transpose((((echo(step((X+transpose(X,12) ) ,12) ,4,6) +arpeggio((X+transpose(((X+transpose(X,4) ) +transpose(X,7) ) ,12) ) ) ) +((X+transpose(X,4) ) +transpose(X,7) ) ) +transpose(((arpeggio(shuffle(X) ) +transpose(step((arpeggio(transpose((X+transpose(arpeggio((X+transpose(X,12) ) ) ,12) ) ,-5) ) |transpose(arpeggio(((X+transpose(X,4) ) +transpose(X,7) ) ) ,4) ) ,12) ,7) ) +transpose(step(echo(echo(step(((((X+transpose(X,4) ) +transpose(X,7) ) +transpose(transpose(X,-7) ,4) ) +transpose(step(X,12) ,7) ) ,12) ,4,6) ,4,6) ,12) ,12) ) ,7) ) ,7) ) ,12) ) +transpose((transpose(transpose(step(((arpeggio(step(step(X,12) ,12) ) +echo(X,4,6) ) |(echo((X|X) ,4,6) +arpeggio(X) ) ) ,12) ,4) ,-5) +transpose((transpose(arpeggio(transpose(step(((arpeggio(step(X,12) ) +transpose((step((X|X) ,12) +transpose(((arpeggio(X) +transpose(echo(X,4,6) ,4) ) +transpose(X,7) ) ,7) ) ,4) ) +transpose(transpose(transpose(X,-5) ,-5) ,7) ) ,12) ,4) ) ,4) +transpose((echo(transpose((((((shuffle(transpose(X,-7) ) +transpose(step((X|X) ,12) ,7) ) +transpose(step(transpose(X,-7) ,12) ,4) ) +transpose(step((X+transpose(X,12) ) ,12) ,7) ) +transpose(transpose(((transpose(X,-5) +transpose(transpose(X,4) ,12) ) +transpose(transpose(X,-5) ,7) ) ,-5) ,4) ) +transpose((echo(((X+transpose(X,7) ) |arpeggio(X) ) ,4,6) +transpose(shuffle(arpeggio(X) ) ,7) ) ,7) ) ,4) ,4,6) |step(shuffle((((((arpeggio(transpose(X,-7) ) +(step(X,12) +transpose((X+transpose(X,12) ) ,12) ) ) +((echo((X+transpose(((X+transpose(X,4) ) +transpose(X,7) ) ,12) ) ,4,6) +transpose((transpose(X,-5) +transpose(X,4) ) ,4) ) +transpose(transpose(X,4) ,7) ) ) +transpose(shuffle((transpose(X,-7) +transpose((transpose((X|X) ,-7) +transpose((X+transpose(X,12) ) ,7) ) ,12) ) ) ,7) ) +transpose(transpose((X+transpose((echo(X,4,6) +transpose((X+transpose(X,12) ) ,7) ) ,7) ) ,-5) ,4) ) +transpose((((X+transpose(X,12) ) +transpose(((echo(X,4,6) +transpose(transpose(shuffle(X) ,4) ,7) ) +transpose(transpose(transpose(transpose(X,-5) ,-7) ,4) ,7) ) ,4) ) +transpose((transpose((arpeggio(X) +(X+transpose(X,12) ) ) ,4) +((transpose(echo(X,4,6) ,4) +transpose(X,7) ) +transpose(transpose(((X+transpose(X,4) ) +transpose(X,7) ) ,-5) ,12) ) ) ,7) ) ,7) ) ) ,12) ) ,7) ) ,12) ) ,7) ) ,-7) ,-7) ,12) ) ,-7) +transpose((shuffle(transpose((arpeggio(echo(shuffle(step((((transpose(arpeggio(X) ,4) +transpose(((transpose((((transpose(X,4) +transpose(X,-7) ) +transpose(step(X,12) ,4) ) +transpose(echo(X,4,6) ,7) ) ,-7) +transpose(transpose((((((X+transpose(X,4) ) +transpose(X,7) ) +transpose(echo(((X+transpose(X,4) ) +transpose(X,7) ) ,4,6) ,4) ) +transpose((shuffle(X) +transpose(X,7) ) ,7) ) +transpose(shuffle(shuffle(X) ) ,12) ) ,4) ,12) ) +transpose(((transpose((((X+transpose(X,7) ) +step(X,12) ) +transpose(X,7) ) ,-7) +transpose(((transpose(transpose(X,-5) ,-7) +transpose(((X+transpose(X,4) ) +transpose(X,7) ) ,7) ) +transpose(echo(X,4,6) ,12) ) ,7) ) +transpose(transpose((((X+transpose(X,12) ) +transpose((((X+transpose(X,12) ) +transpose(X,4) ) +transpose((X+transpose(X,12) ) ,7) ) ,7) ) +transpose(transpose(transpose(transpose(X,-7) ,-7) ,4) ,7) ) ,-7) ,7) ) ,12) ) ,7) ) +transpose(((arpeggio(((step(X,12) +transpose(X,12) ) +transpose(arpeggio(arpeggio(X) ) ,7) ) ) +transpose(transpose(step(transpose(((X+transpose(X,4) ) +transpose(X,7) ) ,-7) ,12) ,4) ,12) ) +transpose(arpeggio((echo(X,4,6) |((X+transpose(X,4) ) +transpose(X,7) ) ) ) ,7) ) ,4) ) +transpose(shuffle(echo(echo((shuffle(X) |transpose(X,-7) ) ,4,6) ,4,6) ) ,7) ) ,12) ) ,4,6) ) +(transpose(((((step((arpeggio((echo((transpose((X+transpose(X,12) ) ,-7) |transpose(X,-5) ) ,4,6) +transpose(((echo(echo(X,4,6) ,4,6) +transpose(arpeggio(arpeggio(X) ) ,4) ) +transpose(step(X,12) ,7) ) ,7) ) ) +transpose(step(shuffle(step((X+transpose(X,7) ) ,12) ) ,12) ,7) ) ,12) +transpose(shuffle((echo(transpose(X,4) ,4,6) +transpose((shuffle(transpose(transpose(X,-7) ,-5) ) +arpeggio(((X+X) |X) ) ) ,7) ) ) ,12) ) +transpose(echo((shuffle(((shuffle((echo(X,4,6) +transpose(X,7) ) ) +transpose((X+X) ,12) ) +transpose(((transpose(X,-7) +transpose((X+transpose(X,7) ) ,7) ) +transpose(step(transpose(echo(X,4,6) ,-5) ,12) ,12) ) ,7) ) ) +transpose((arpeggio(arpeggio(transpose(shuffle(arpeggio(X) ) ,-5) ) ) +shuffle(echo(shuffle((transpose(X,4) +transpose(step(X,12) ,7) ) ) ,4,6) ) ) ,12) ) ,4,6) ,4) ) +transpose(shuffle(shuffle(transpose(((transpose(X,4) +transpose((X|X) ,12) ) +step(step(((X+transpose(X,7) ) +transpose(((X+transpose(X,4) ) +transpose(X,7) ) ,12) ) ,12) ,12) ) ,-7) ) ) ,7) ) +transpose(((arpeggio(((transpose(echo(shuffle(X) ,4,6) ,-7) +transpose(((step(X,12) +transpose(transpose(X,-5) ,4) ) +transpose(((X+transpose((X+transpose(X,7) ) ,4) ) +transpose(X,7) ) ,7) ) ,4) ) +transpose(shuffle(X) ,7) ) ) +transpose(transpose((transpose(transpose((echo(transpose(X,-5) ,4,6) +(X+X) ) ,-7) ,4) +(transpose(((step(X,12) +X) +transpose(((X+transpose(X,12) ) +transpose((X|X) ,7) ) ,12) ) ,-5) +(((transpose((echo(X,4,6) +transpose(X,7) ) ,-7) |((shuffle(X) +transpose(step(arpeggio(X) ,12) ,4) ) +transpose(X,7) ) ) +transpose(echo((X+transpose(X,12) ) ,4,6) ,4) ) +transpose(shuffle((arpeggio(X) +X) ) ,7) ) ) ) ,4) ,4) ) +transpose(transpose(arpeggio(((echo((X+transpose((X+transpose(X,7) ) ,7) ) ,4,6) +transpose(step((X+transpose(X,12) ) ,12) ,12) ) +transpose((arpeggio(X) +transpose(((transpose(arpeggio(X) ,4) +transpose((transpose(X,4) +transpose((X+transpose(X,12) ) ,12) ) ,4) ) +transpose(transpose(step(X,12) ,-5) ,7) ) ,12) ) ,12) ) ) ,-5) ,7) ) ,12) ) ,-7) |((transpose(((shuffle(transpose((transpose(((((X+transpose(X,7) ) |transpose(X,-5) ) +transpose(X,7) ) |transpose((X+transpose(X,12) ) ,-7) ) ,4) +transpose(shuffle(step((transpose(echo(X,4,6) ,4) |arpeggio(echo(X,4,6) ) ) ,12) ) ,12) ) ,-5) ) +transpose(arpeggio(transpose(transpose(((((transpose(X,-5) +transpose(arpeggio(X) ,4) ) +transpose(step(X,12) ,7) ) +transpose((X+X) ,7) ) |echo(arpeggio(arpeggio(X) ) ,4,6) ) ,-5) ,4) ) ,4) ) +transpose(shuffle((arpeggio(transpose(step((X+transpose(X,12) ) ,12) ,-7) ) +transpose(transpose(transpose((transpose(echo(X,4,6) ,4) +transpose(transpose(arpeggio(step(X,12) ) ,-5) ,7) ) ,-5) ,-7) ,12) ) ) ,7) ) ,4) +transpose(transpose(transpose(transpose((shuffle(step(X,12) ) +transpose(step(echo(X,4,6) ,12) ,12) ) ,-5) ,-7) ,4) ,4) ) +transpose(echo(step(step(transpose(((((X+transpose(X,12) ) +transpose(arpeggio(X) ,7) ) +transpose((X+transpose(X,12) ) ,12) ) +transpose((transpose(transpose((transpose(X,4) +transpose((X+transpose(X,12) ) ,7) ) ,-5) ,4) +transpose(step(shuffle((((X+transpose(X,4) ) +transpose(X,7) ) +transpose(arpeggio(X) ,7) ) ) ,12) ,12) ) ,12) ) ,-5) ,12) ,12) ,4,6) ,7) ) ) ) ,-5) ) +transpose(((arpeggio(((transpose(((shuffle(echo((shuffle(X) +transpose(transpose(((X+transpose(X,4) ) +transpose(X,7) ) ,4) ,7) ) ,4,6) ) +transpose((((transpose(shuffle((step(X,12) +transpose(shuffle(X) ,12) ) ) ,-7) +transpose(echo(transpose(((X+transpose(X,7) ) +transpose(((X+transpose(X,4) ) +transpose(X,7) ) ,12) ) ,4) ,4,6) ,12) ) +(shuffle((shuffle(X) +X) ) +transpose(shuffle(arpeggio(X) ) ,12) ) ) +transpose(((((((X+transpose(X,7) ) |shuffle(X) ) +transpose((transpose(X,4) +transpose(X,7) ) ,4) ) +transpose((arpeggio(X) +X) ,7) ) |arpeggio(((transpose(X,-7) +transpose(X,7) ) +(shuffle(X) |X) ) ) ) +transpose(transpose(X,4) ,7) ) ,7) ) ,12) ) +transpose((transpose(transpose((transpose(echo(X,4,6) ,4) +transpose(shuffle((X+transpose((X+X) ,12) ) ) ,7) ) ,4) ,-7) +transpose(step(((shuffle(step(step(X,12) ,12) ) +transpose(transpose((shuffle(X) +transpose((X|X) ,12) ) ,-5) ,12) ) +transpose(shuffle((X+X) ) ,-5) ) ,12) ,7) ) ,12) ) ,4) +transpose((arpeggio(arpeggio(step(arpeggio((transpose(X,4) +((X+transpose(X,4) ) +transpose(X,7) ) ) ) ,12) ) ) +transpose(step((shuffle(((arpeggio(transpose(((X+transpose(X,7) ) +transpose(X,12) ) ,4) ) +transpose(echo((transpose((arpeggio(X) |(X+X) ) ,-5) +transpose((((X+transpose((X|X) ,7) ) +transpose(arpeggio(X) ,4) ) +transpose(((X+transpose(X,4) ) +transpose(X,7) ) ,7) ) ,12) ) ,4,6) ,7) ) +transpose(transpose(echo(step(X,12) ,4,6) ,-7) ,12) ) ) +transpose(arpeggio((step(echo(X,4,6) ,12) +transpose(echo((((arpeggio(X) +arpeggio(X) ) +transpose((arpeggio((X+X) ) +transpose(echo(transpose(X,-7) ,4,6) ,7) ) ,4) ) +transpose(transpose(transpose((X|X) ,-5) ,4) ,7) ) ,4,6) ,12) ) ) ,12) ) ,12) ,7) ) ,4) ) +transpose(echo((transpose(((((arpeggio(X) +transpose(shuffle(X) ,4) ) +transpose((X+transpose(echo(X,4,6) ,7) ) ,7) ) +transpose((X|(X+transpose(X,7) ) ) ,7) ) +transpose((X+transpose(transpose(X,-7) ,7) ) ,7) ) ,-5) +transpose((transpose((step((((X|X) +transpose(X,12) ) +transpose(((transpose(X,-5) +transpose(X,4) ) +transpose((X|X) ,7) ) ,12) ) ,12) |transpose(arpeggio(echo(X,4,6) ) ,4) ) ,4) +(((arpeggio(echo(arpeggio(X) ,4,6) ) +transpose((X+transpose(X,12) ) ,-5) ) +transpose(transpose((X+transpose(X,12) ) ,-5) ,7) ) |(transpose(X,-5) +transpose(((transpose(X,-5) +transpose((X+transpose(X,7) ) ,4) ) +transpose((X+transpose(X,7) ) ,7) ) ,12) ) ) ) ,7) ) ,4,6) ,7) ) ) +transpose((echo((echo(((transpose(echo(echo(step(shuffle(X) ,12) ,4,6) ,4,6) ,-5) |arpeggio(transpose((step((echo(shuffle(X) ,4,6) +transpose((X|X) ,12) ) ,12) +transpose(shuffle((arpeggio((((X+transpose(X,4) ) +transpose(X,7) ) +transpose(X,12) ) ) +step(((echo(X,4,6) +transpose(transpose(X,4) ,4) ) +transpose((X+transpose(X,12) ) ,7) ) ,12) ) ) ,12) ) ,-7) ) ) |transpose(arpeggio(shuffle(arpeggio(echo(X,4,6) ) ) ) ,-5) ) ,4,6) +transpose((((((arpeggio((X+transpose((X+transpose(step(X,12) ,12) ) ,7) ) ) +transpose(((X+transpose((X+transpose(X,7) ) ,12) ) +transpose(echo(X,4,6) ,7) ) ,7) ) |arpeggio(X) ) +transpose(((shuffle(((X+transpose(X,4) ) +transpose(X,7) ) ) +transpose(shuffle(step(X,12) ) ,7) ) +echo((X+transpose((X+transpose(X,12) ) ,12) ) ,4,6) ) ,12) ) +transpose(((echo(shuffle(echo(X,4,6) ) ,4,6) +transpose(((((echo(transpose((X|X) ,-7) ,4,6) +transpose(echo(((X+X) +transpose((X|X) ,7) ) ,4,6) ,4) ) +transpose(((step((X+transpose((X|X) ,12) ) ,12) +transpose(transpose(X,4) ,4) ) +transpose((((X+transpose(X,7) ) +transpose(X,12) ) |(X|X) ) ,7) ) ,7) ) +transpose(transpose((arpeggio(arpeggio((X+transpose(X,7) ) ) ) +transpose(shuffle(arpeggio(X) ) ,7) ) ,-7) ,4) ) +transpose((shuffle(echo(X,4,6) ) +transpose(arpeggio(step(((X+(X|X) ) +transpose(X,12) ) ,12) ) ,7) ) ,7) ) ,4) ) +transpose(transpose(((((((X+transpose(X,7) ) +transpose(X,4) ) +transpose(transpose(X,4) ,7) ) +transpose(shuffle(X) ,7) ) +transpose(transpose(((X+X) +transpose(echo(X,4,6) ,12) ) ,4) ,4) ) +transpose(step(transpose(arpeggio(X) ,-5) ,12) ,7) ) ,4) ,7) ) ,12) ) +step(shuffle(step(transpose(step(step(transpose(transpose(X,-5) ,4) ,12) ,12) ,-7) ,12) ) ,12) ) ,7) ) ,4,6) +(transpose((((transpose(step(echo(shuffle(X) ,4,6) ,12) ,4) +transpose(step(transpose(transpose(transpose((X+transpose(X,7) ) ,4) ,4) ,-5) ,12) ,-7) ) +((shuffle(arpeggio((transpose(transpose(arpeggio(X) ,-7) ,4) |step(step(transpose(shuffle(X) ,4) ,12) ,12) ) ) ) +transpose((step(echo(X,4,6) ,12) +transpose(step(((((echo(X,4,6) |X) |arpeggio(X) ) +transpose(echo(X,4,6) ,4) ) +transpose(transpose(transpose(arpeggio(X) ,-5) ,-7) ,7) ) ,12) ,7) ) ,12) ) +transpose((transpose(transpose((transpose(transpose(X,-5) ,-5) +transpose(transpose((transpose(X,4) +transpose(X,7) ) ,4) ,12) ) ,-7) ,-7) +transpose(transpose(transpose(echo((((((X+transpose(X,4) ) +transpose(X,7) ) +transpose(transpose(X,-7) ,12) ) +transpose((X+X) ,4) ) +transpose(X,7) ) ,4,6) ,4) ,4) ,7) ) ,7) ) ) |(arpeggio((step(X,12) +transpose(transpose((X+transpose(X,7) ) ,4) ,7) ) ) |((transpose(transpose(transpose((transpose(X,-7) +transpose(shuffle(arpeggio(X) ) ,7) ) ,-7) ,-5) ,-7) +transpose(echo(transpose(transpose((X+transpose(X,7) ) ,4) ,-5) ,4,6) ,7) ) +transpose(transpose(((echo((X+transpose(transpose(X,-5) ,12) ) ,4,6) +transpose(transpose(echo(X,4,6) ,4) ,4) ) +transpose(((((X+transpose((X+X) ,12) ) +transpose(transpose((X+transpose(X,7) ) ,-7) ,7) ) +transpose((X+(X+X) ) ,7) ) +transpose((X+transpose(((X+transpose(X,4) ) +transpose(X,7) ) ,7) ) ,12) ) ,7) ) ,4) ,7) ) ) ) ,-7) +transpose((step(arpeggio(transpose(transpose((transpose(transpose(shuffle(echo(X,4,6) ) ,-7) ,-5) +transpose(shuffle(shuffle((((((X+transpose(((X+transpose(X,4) ) +transpose(X,7) ) ,12) ) +transpose(arpeggio(transpose((X+X) ,4) ) ,4) ) +transpose(shuffle(((X+transpose(X,12) ) +transpose((X+X) ,7) ) ) ,7) ) +transpose((echo((X+X) ,4,6) +transpose(transpose((X+X) ,-7) ,7) ) ,4) ) +transpose(((echo(arpeggio((X+transpose(X,12) ) ) ,4,6) +transpose((((X+transpose(X,12) ) +transpose(arpeggio(X) ,4) ) +transpose(transpose((X+X) ,-5) ,7) ) ,4) ) +transpose((X+X) ,7) ) ,7) ) ) ) ,7) ) ,4) ,-5) ) ,12) +transpose(transpose((transpose(transpose(transpose(((((arpeggio((X+(X|X) ) ) +transpose((((X+transpose(X,12) ) +transpose(((X+transpose(X,4) ) +transpose(X,7) ) ,7) ) +transpose(((X+transpose(X,7) ) +transpose(((X+transpose(X,4) ) +transpose(X,7) ) ,12) ) ,12) ) ,4) ) +transpose(((X|shuffle(X) ) +transpose(((X+transpose(X,12) ) +transpose(echo(X,4,6) ,12) ) ,12) ) ,7) ) +transpose(transpose(X,-5) ,4) ) +transpose(((shuffle((X+transpose(X,12) ) ) +transpose(step(step(arpeggio(X) ,12) ,12) ,4) ) +transpose(transpose((X+transpose(X,7) ) ,4) ,7) ) ,7) ) ,-5) ,-5) ,-7) +transpose((((step(((shuffle(transpose(X,4) ) +transpose(arpeggio((X+transpose(((X+transpose(X,4) ) +transpose(X,7) ) ,12) ) ) ,4) ) +transpose((X+X) ,7) ) ,12) +transpose(echo(transpose((transpose(X,-5) +transpose(((X+transpose((X|X) ,4) ) +transpose(echo(shuffle(X) ,4,6) ,7) ) ,7) ) ,-7) ,4,6) ,7) ) |transpose(transpose(arpeggio((transpose(transpose(X,-7) ,4) |(((X+transpose(X,4) ) +transpose(X,7) ) +transpose(X,7) ) ) ) ,-5) ,-7) ) |arpeggio(((((X+X) +transpose(shuffle(shuffle((X+transpose(X,12) ) ) ) ,7) ) |step(arpeggio(X) ,12) ) +(arpeggio(transpose((X+transpose(X,12) ) ,4) ) +transpose(arpeggio(shuffle(step(X,12) ) ) ,12) ) ) ) ) ,12) ) ,-5) ,7) ) ,12) ) ) ,4) ) +transpose(arpeggio(echo(((shuffle(transpose(transpose((((shuffle(X) +transpose(X,4) ) +transpose((X+transpose(X,7) ) ,7) ) |((arpeggio(X) +transpose((X|X) ,4) ) +transpose(shuffle(X) ,7) ) ) ,-7) ,-7) ) +transpose(((((arpeggio((((X+X) +transpose(transpose(X,-5) ,4) ) +transpose(shuffle((X+transpose(transpose(X,-7) ,12) ) ) ,7) ) ) +transpose(arpeggio((transpose(shuffle((X+transpose(X,12) ) ) ,4) +transpose(shuffle(step(step((X+transpose(X,7) ) ,12) ,12) ) ,12) ) ) ,7) ) +transpose(((step((((X+transpose(X,4) ) +transpose((X+transpose(X,12) ) ,7) ) +transpose(shuffle((X+X) ) ,7) ) ,12) +transpose(transpose(arpeggio(echo(arpeggio(arpeggio(X) ) ,4,6) ) ,-5) ,12) ) +shuffle(transpose(arpeggio(echo((X|X) ,4,6) ) ,-5) ) ) ,4) ) +transpose((((((echo(step(X,12) ,4,6) +transpose((((echo(X,4,6) +transpose((X+transpose(X,12) ) ,4) ) +transpose(X,7) ) |(X+X) ) ,4) ) +transpose(((X|X) +transpose(X,4) ) ,7) ) +transpose(((echo(echo(X,4,6) ,4,6) |X) +(step(X,12) +((echo(X,4,6) +transpose(X,4) ) +transpose(X,7) ) ) ) ,7) ) +transpose((shuffle(X) +transpose(transpose((X+X) ,4) ,12) ) ,7) ) |arpeggio(((((transpose(X,-7) +transpose(transpose(transpose(X,-5) ,4) ,4) ) +transpose(((X+transpose(X,4) ) +transpose(X,7) ) ,7) ) +transpose(X,4) ) +transpose(shuffle(step(step((X+transpose(X,7) ) ,12) ,12) ) ,7) ) ) ) ,7) ) |step((transpose(arpeggio(((X+transpose(X,7) ) +transpose(X,12) ) ) ,-7) +transpose(echo(X,4,6) ,12) ) ,12) ) ,7) ) +transpose(((arpeggio(step(((step(((X+transpose(X,4) ) +transpose(X,7) ) ,12) |((X+transpose(X,4) ) +transpose(X,7) ) ) +((transpose(echo(X,4,6) ,-7) +transpose(transpose(X,4) ,4) ) +transpose(X,7) ) ) ,12) ) +transpose(echo(arpeggio(echo(X,4,6) ) ,4,6) ,7) ) +transpose(transpose(shuffle(((arpeggio((X|X) ) +transpose(((shuffle(X) |transpose(X,4) ) +transpose(((X+transpose(arpeggio(X) ,4) ) +transpose(((X+transpose(X,4) ) +transpose(X,7) ) ,7) ) ,12) ) ,12) ) +transpose((X+transpose(X,7) ) ,-7) ) ) ,-7) ,12) ) ,7) ) ,4,6) ) ,7) ) ,12) ) ,7) ) random seed used was 240378995

The algorithm for Expresso is written in KeyKit, and here's the source code.