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 16 generations the expression "X" became this: step(((((echo(echo(shuffle(((echo((((X+transpose(((X+transpose(X,4) ) +transpose(X,7) ) ,4) ) +transpose(arpeggio(((X+transpose(X,4) ) +transpose(X,7) ) ) ,7) ) +transpose(((shuffle(X) +transpose((X|X) ,4) ) +transpose(((X+X) +transpose(echo(X,4,6) ,7) ) ,7) ) ,12) ) ,4,6) +transpose(shuffle(((X+transpose(X,12) ) +transpose(arpeggio((echo((X+transpose(X,12) ) ,4,6) +transpose(transpose(X,-7) ,12) ) ) ,7) ) ) ,4) ) +transpose((arpeggio((((X+transpose(X,12) ) +transpose(X,4) ) +transpose((X|X) ,7) ) ) |(shuffle((X+transpose((X+transpose(X,12) ) ,7) ) ) +transpose((shuffle(((X+transpose(X,4) ) +transpose(X,7) ) ) +transpose((arpeggio(X) +transpose((X+transpose(X,7) ) ,12) ) ,12) ) ,12) ) ) ,7) ) ) ,4,6) ,4,6) +transpose((((transpose(arpeggio(((X+transpose(X,7) ) +transpose(step(X,12) ,12) ) ) ,-7) +((step(echo(step(transpose(step(X,12) ,-7) ,12) ,4,6) ,12) +transpose(shuffle(echo((transpose(transpose(((transpose(X,-7) +transpose(X,12) ) +transpose(echo(X,4,6) ,12) ) ,-5) ,-5) +transpose(echo(step((X+transpose(arpeggio(X) ,12) ) ,12) ,4,6) ,12) ) ,4,6) ) ,4) ) +transpose(arpeggio(transpose(echo(X,4,6) ,-7) ) ,7) ) ) +transpose((arpeggio(echo(((transpose(X,-7) +transpose(transpose(((X+transpose(X,12) ) +transpose((X+X) ,12) ) ,-7) ,7) ) +transpose((step(X,12) +transpose(((X+X) +transpose((X|X) ,12) ) ,7) ) ,7) ) ,4,6) ) +transpose((transpose((echo(((X|X) +transpose(shuffle(X) ,12) ) ,4,6) +transpose(((X+transpose(X,12) ) +transpose((shuffle(transpose(X,-7) ) +transpose(transpose(X,-5) ,4) ) ,12) ) ,7) ) ,-7) +transpose((step(step((((X+transpose(X,12) ) +transpose((X+transpose(X,7) ) ,4) ) +transpose(((X+transpose(X,4) ) +transpose(X,7) ) ,7) ) ,12) ,12) +step((step((X+transpose(X,12) ) ,12) +step(X,12) ) ,12) ) ,7) ) ,12) ) ,4) ) +transpose(transpose(step(arpeggio((transpose(X,4) +transpose(arpeggio(X) ,7) ) ) ,12) ,4) ,7) ) ,12) ) +transpose((((shuffle(transpose((echo((transpose(X,4) +transpose(X,4) ) ,4,6) +transpose((((X+transpose(step(X,12) ,7) ) +transpose((((X+transpose(X,4) ) +transpose(X,7) ) +transpose(step(transpose(X,4) ,12) ,12) ) ,7) ) +transpose(shuffle(((X+X) |X) ) ,7) ) ,12) ) ,-5) ) |((transpose(echo(transpose((step(transpose(X,4) ,12) |step(transpose(X,4) ,12) ) ,4) ,4,6) ,-7) +transpose(step(((X|echo(transpose(X,4) ,4,6) ) +transpose((echo(step(transpose(X,4) ,12) ,4,6) +transpose(echo(X,4,6) ,7) ) ,12) ) ,12) ,4) ) +transpose((transpose(((X+transpose(X,12) ) +transpose(((X+transpose(X,4) ) +transpose(X,7) ) ,12) ) ,-5) +transpose(transpose(arpeggio(arpeggio((((X+X) +transpose(step(X,12) ,4) ) +transpose(arpeggio(X) ,7) ) ) ) ,4) ,12) ) ,7) ) ) +transpose(((((((((echo(((X+transpose(X,4) ) +transpose(X,7) ) ,4,6) +transpose(echo(step(X,12) ,4,6) ,12) ) +transpose(echo(arpeggio(step((X+transpose(X,12) ) ,12) ) ,4,6) ,4) ) +transpose((((echo(X,4,6) +transpose(echo(X,4,6) ,4) ) +transpose(arpeggio(transpose(X,-5) ) ,7) ) |((echo(arpeggio(X) ,4,6) +transpose(transpose(step(step(X,12) ,12) ,-7) ,4) ) +transpose(transpose((X+transpose(X,12) ) ,4) ,7) ) ) ,7) ) +transpose((((echo((shuffle(step(X,12) ) +transpose(X,7) ) ,4,6) +transpose((echo((echo(X,4,6) |((X+transpose(X,4) ) +transpose(X,7) ) ) ,4,6) +transpose(transpose(X,4) ,12) ) ,7) ) +transpose((echo((((step((X+transpose(X,7) ) ,12) +transpose(echo((X+transpose(X,12) ) ,4,6) ,4) ) +transpose(X,7) ) +transpose(echo(X,4,6) ,7) ) ,4,6) +transpose((step((X+transpose(X,12) ) ,12) +transpose(echo(transpose(echo(((X+transpose(X,4) ) +transpose(X,7) ) ,4,6) ,4) ,4,6) ,7) ) ,7) ) ,4) ) +transpose(echo(transpose(shuffle(transpose(X,4) ) ,4) ,4,6) ,7) ) ,12) ) +step((((step(transpose(X,-5) ,12) +transpose(((X+transpose(echo(transpose(X,-5) ,4,6) ,4) ) +transpose(arpeggio(X) ,7) ) ,12) ) +transpose((arpeggio(transpose(X,-7) ) +transpose(echo(((X+transpose(step(X,12) ,4) ) +transpose((X+transpose(X,7) ) ,7) ) ,4,6) ,7) ) ,12) ) |shuffle(((X|X) |(step(X,12) +transpose(X,7) ) ) ) ) ,12) ) +transpose((transpose(arpeggio(arpeggio(echo(X,4,6) ) ) ,-7) +transpose((step(transpose(X,4) ,12) +transpose(((echo(arpeggio(((X|X) |(X|X) ) ) ,4,6) +transpose(echo((step(X,12) +transpose((X+transpose((X+transpose(X,7) ) ,7) ) ,12) ) ,4,6) ,4) ) +transpose((((((((X+transpose(X,4) ) +transpose(X,7) ) +transpose(X,4) ) +transpose(X,7) ) +transpose(((X+transpose(X,12) ) +transpose(X,7) ) ,7) ) +transpose((((X+transpose(X,4) ) +transpose((X+transpose(X,7) ) ,7) ) |((X+transpose(X,12) ) |X) ) ,12) ) +transpose(echo(shuffle(X) ,4,6) ,12) ) ,7) ) ,7) ) ,7) ) ,4) ) +transpose((step(transpose(echo((X+transpose(X,12) ) ,4,6) ,-5) ,12) +transpose((shuffle(((X+transpose((X+transpose(X,7) ) ,4) ) +transpose(echo(X,4,6) ,7) ) ) +step(transpose(transpose(transpose(step((X+transpose(((X+transpose(X,4) ) +transpose(X,7) ) ,12) ) ,12) ,-7) ,-5) ,4) ,12) ) ,12) ) ,7) ) +transpose(shuffle(arpeggio(echo(shuffle(transpose(transpose(transpose(echo(X,4,6) ,-7) ,4) ,4) ) ,4,6) ) ) ,7) ) ,4) ) +transpose(arpeggio((echo(((shuffle(transpose((step(echo(X,4,6) ,12) +transpose((X|X) ,-7) ) ,4) ) +transpose(((step(((X|X) +(((X+transpose(X,12) ) +transpose(X,4) ) +transpose(X,7) ) ) ,12) |(((transpose(X,-7) +transpose(X,4) ) +transpose(transpose(X,4) ,7) ) +((X+transpose(X,4) ) +transpose((X+transpose(X,12) ) ,7) ) ) ) +transpose(transpose(X,-5) ,4) ) ,12) ) |transpose((((X+X) +transpose(((X+transpose(X,4) ) +transpose(shuffle(X) ,7) ) ,4) ) +transpose(shuffle(X) ,7) ) ,-7) ) ,4,6) +transpose(transpose(((transpose((transpose(transpose(arpeggio((X+transpose(X,12) ) ) ,-5) ,-7) +transpose(arpeggio(arpeggio((X+transpose(X,12) ) ) ) ,12) ) ,4) +(step((((X+transpose(X,12) ) +transpose(transpose(X,-5) ,12) ) +transpose(transpose(X,-5) ,7) ) ,12) +transpose(echo(((transpose(X,4) +transpose((X+transpose(arpeggio(X) ,7) ) ,4) ) +transpose(arpeggio(X) ,7) ) ,4,6) ,12) ) ) +transpose(transpose(transpose(echo(arpeggio((arpeggio(echo(X,4,6) ) +transpose((X+(X+transpose((X+transpose(X,12) ) ,12) ) ) ,12) ) ) ,4,6) ,4) ,-5) ,7) ) ,4) ,7) ) ) ,7) ) ,4) ) +transpose((echo(shuffle(arpeggio(((arpeggio(transpose(echo(X,4,6) ,-5) ) +transpose(echo(echo(X,4,6) ,4,6) ,7) ) |((((step((X+transpose(X,7) ) ,12) +transpose((X+transpose(X,12) ) ,12) ) +X) |transpose(shuffle((((X+transpose(X,7) ) +transpose(X,4) ) +transpose(X,7) ) ) ,-5) ) +transpose(((X+transpose(X,12) ) +transpose(echo(((X+transpose(X,4) ) +transpose(X,7) ) ,4,6) ,7) ) ,12) ) ) ) ) ,4,6) +transpose((step(transpose((echo(step(shuffle(((X+X) +transpose(step(X,12) ,7) ) ) ,12) ,4,6) +transpose(arpeggio((((arpeggio(X) +transpose((((X+transpose(X,12) ) +transpose((X+transpose(X,12) ) ,4) ) +transpose(X,7) ) ,7) ) +transpose((X+transpose(arpeggio(X) ,12) ) ,12) ) +arpeggio(X) ) ) ,12) ) ,4) ,12) +step(echo(((step(transpose(X,-5) ,12) +transpose(step(((((X+transpose(X,4) ) +transpose(X,7) ) +transpose(X,4) ) +transpose(arpeggio(X) ,7) ) ,12) ,4) ) +transpose(transpose(shuffle((X+transpose((transpose(X,-5) +transpose(echo(X,4,6) ,12) ) ,12) ) ) ,4) ,7) ) ,4,6) ,12) ) ,7) ) ,7) ) +transpose((shuffle(((arpeggio((((arpeggio(arpeggio(transpose(X,-5) ) ) +transpose(((step(X,12) +echo(X,4,6) ) |(echo((X+X) ,4,6) +transpose(transpose(transpose(X,-5) ,4) ,12) ) ) ,4) ) +transpose((((((X+transpose(X,12) ) +transpose((X+transpose(X,7) ) ,12) ) +transpose(echo(X,4,6) ,4) ) +transpose(echo(shuffle(((X+transpose(X,4) ) +transpose(X,7) ) ) ,4,6) ,7) ) +transpose((X|X) ,7) ) ,7) ) +transpose(shuffle(((echo(transpose(((X+transpose(X,12) ) +transpose((X+X) ,12) ) ,4) ,4,6) +transpose((((transpose(X,-7) +transpose(X,7) ) +transpose((X+transpose(X,12) ) ,4) ) +transpose(X,7) ) ,4) ) +transpose((transpose(transpose(X,-5) ,-5) +transpose(shuffle(X) ,12) ) ,7) ) ) ,12) ) ) +transpose((transpose(((X+transpose((X+X) ,7) ) +arpeggio((X+transpose(transpose(X,-7) ,12) ) ) ) ,-7) +(transpose(arpeggio(step(transpose(X,4) ,12) ) ,-5) +transpose((arpeggio((X+transpose(X,7) ) ) |(((step(X,12) +transpose((X|echo(X,4,6) ) ,12) ) +transpose((shuffle(X) +transpose(arpeggio((X+X) ) ,7) ) ,4) ) +transpose(arpeggio((arpeggio(X) |(X+transpose(X,7) ) ) ) ,7) ) ) ,7) ) ) ,7) ) +transpose(arpeggio(shuffle((X|X) ) ) ,7) ) ) +transpose((shuffle(transpose((((step(((arpeggio(X) |(X+transpose(X,7) ) ) +transpose(X,7) ) ,12) |((step(X,12) +transpose((X+transpose(X,12) ) ,4) ) +transpose(transpose(X,-7) ,7) ) ) +transpose(arpeggio((((X+transpose(X,12) ) |X) |(X+transpose(transpose((X|X) ,-5) ,12) ) ) ) ,12) ) +transpose((((transpose(transpose(step(X,12) ,-5) ,4) +transpose(((echo(X,4,6) +transpose(arpeggio(X) ,4) ) +transpose(transpose((X+transpose(X,7) ) ,-5) ,7) ) ,4) ) +transpose(step(step(step(X,12) ,12) ,12) ,7) ) +step(X,12) ) ,12) ) ,-5) ) +transpose(((((step(echo(shuffle((X+transpose(step(X,12) ,12) ) ) ,4,6) ,12) +transpose(((arpeggio(echo(step(X,12) ,4,6) ) +transpose(step(((echo(X,4,6) +transpose(((((X+transpose(X,4) ) +transpose(X,7) ) +transpose((X+transpose(X,7) ) ,4) ) +transpose(((X+transpose(X,4) ) +transpose(X,7) ) ,7) ) ,4) ) +transpose((step(X,12) +X) ,7) ) ,12) ,4) ) +transpose(echo((arpeggio(X) +transpose((X+transpose(X,12) ) ,12) ) ,4,6) ,7) ) ,4) ) +transpose(step(((echo(step(transpose(X,4) ,12) ,4,6) +transpose(step(echo(arpeggio((X+transpose(step(X,12) ,12) ) ) ,4,6) ,12) ,4) ) +transpose((arpeggio(step((X+X) ,12) ) +transpose(echo(((X+transpose(X,12) ) +transpose(shuffle(echo(X,4,6) ) ,12) ) ,4,6) ,12) ) ,7) ) ,12) ,7) ) +transpose((echo((echo(echo((X+transpose(X,12) ) ,4,6) ,4,6) +transpose((step((X+X) ,12) +((X|X) +transpose(X,12) ) ) ,7) ) ,4,6) +transpose(shuffle(transpose(arpeggio(transpose((X|X) ,-5) ) ,-7) ) ,12) ) ,4) ) +transpose((((transpose(shuffle(arpeggio(transpose(arpeggio(X) ,-7) ) ) ,4) +transpose(transpose(((X+transpose(X,12) ) +transpose(echo((X+transpose(X,7) ) ,4,6) ,12) ) ,4) ,7) ) +transpose(echo(step(((((((X+transpose(X,4) ) +transpose(X,7) ) +transpose(shuffle(X) ,7) ) +transpose(transpose(X,-7) ,4) ) +transpose(X,7) ) +arpeggio((X+X) ) ) ,12) ,4,6) ,4) ) +transpose(step((((shuffle(transpose(X,-7) ) +transpose(transpose((X+transpose(X,12) ) ,-5) ,7) ) +transpose(shuffle((X+transpose(transpose(X,4) ,12) ) ) ,7) ) +transpose(transpose(echo(((X+transpose(step(X,12) ,4) ) +transpose(transpose(X,-7) ,7) ) ,4,6) ,4) ,12) ) ,12) ,7) ) ,7) ) ,7) ) ,12) ) ,12) ) ,12) random seed used was 234792112 NOTE: Generated phrase was too large ( 9188 ) , it has been truncated at 5000 notes. EXPR = echo(transpose((step(((transpose(X,4) +X) +transpose(((X+transpose(transpose(X,-5) ,4) ) +transpose(echo(X,4,6) ,7) ) ,4) ) ,12) +(((transpose(transpose(((((transpose(echo(X,4,6) ,-7) +transpose(transpose((X|X) ,-7) ,4) ) +transpose((X+transpose(X,7) ) ,7) ) +transpose((((X+transpose(X,4) ) +transpose(X,7) ) +transpose(X,4) ) ,4) ) +transpose((X+transpose(X,7) ) ,7) ) ,-7) ,-7) +transpose(echo(transpose((step(X,12) +X) ,-5) ,4,6) ,4) ) +transpose((((((X+transpose((X+transpose(X,7) ) ,7) ) +transpose(step(transpose(X,4) ,12) ,12) ) +echo(echo(X,4,6) ,4,6) ) |transpose(arpeggio(X) ,4) ) +transpose(echo(((((arpeggio(X) +transpose(transpose(X,-5) ,7) ) +transpose((transpose(X,4) +transpose(((X+X) +transpose((X+X) ,7) ) ,7) ) ,12) ) +transpose(arpeggio(transpose(transpose((X+X) ,-7) ,-5) ) ,4) ) +transpose((((shuffle(X) +transpose((X+X) ,12) ) +transpose((X+transpose(X,12) ) ,-5) ) |step(((X+transpose(X,4) ) +transpose(X,7) ) ,12) ) ,7) ) ,4,6) ,7) ) ,7) ) +transpose(transpose(((transpose(echo(transpose((X+transpose(X,12) ) ,-7) ,4,6) ,4) +transpose(transpose(((shuffle(X) +transpose(X,4) ) +transpose((X+transpose(X,12) ) ,7) ) ,-5) ,4) ) +transpose((((X+step(X,12) ) |echo(echo(X,4,6) ,4,6) ) +transpose(shuffle(arpeggio(X) ) ,7) ) ,7) ) ,-7) ,12) ) ) ,-5) ,4,6) random seed used was 0 EXPR = transpose(shuffle(((transpose((((transpose(transpose(X,4) ,-5) +transpose((X+transpose(X,12) ) ,4) ) +transpose(arpeggio(X) ,7) ) +transpose(transpose(transpose(X,-7) ,-7) ,7) ) ,-7) +transpose(arpeggio((shuffle(step(transpose(transpose(echo(((transpose(X,-5) +transpose((X+transpose(X,12) ) ,4) ) +transpose((X+transpose(X,12) ) ,7) ) ,4,6) ,-7) ,-5) ,12) ) +transpose((((((X+X) +transpose((X+transpose(X,7) ) ,12) ) +transpose(echo((echo(X,4,6) |((X+transpose(X,4) ) +transpose(X,7) ) ) ,4,6) ,12) ) +transpose(((X+transpose(X,7) ) +transpose(((echo(X,4,6) +transpose((X+transpose(X,7) ) ,7) ) +(X+step(arpeggio(X) ,12) ) ) ,7) ) ,4) ) +transpose(transpose(echo((X|X) ,4,6) ,-7) ,7) ) ,7) ) ) ,12) ) |(transpose(transpose(((shuffle(((X|X) +((X+transpose(X,12) ) |X) ) ) +transpose(arpeggio((X+transpose(X,7) ) ) ,4) ) +transpose(shuffle((((X+transpose(X,7) ) +transpose(X,4) ) +transpose(transpose((X+transpose(X,12) ) ,4) ,7) ) ) ,7) ) ,-5) ,-5) |((((((shuffle(X) |(X+transpose(X,7) ) ) +transpose(((step(X,12) +transpose((step(X,12) +((X+transpose(X,4) ) +transpose(X,7) ) ) ,4) ) +transpose((arpeggio(X) |((((X+transpose(X,4) ) +transpose(X,7) ) +transpose(X,4) ) +transpose(X,7) ) ) ,7) ) ,4) ) +transpose(arpeggio(shuffle((transpose(X,4) +transpose(X,12) ) ) ) ,7) ) +transpose(arpeggio(arpeggio((X+transpose((X|X) ,7) ) ) ) ,4) ) +transpose(transpose(((shuffle(X) +transpose(X,12) ) +transpose(transpose((arpeggio(X) +transpose(echo(X,4,6) ,12) ) ,4) ,7) ) ,-7) ,7) ) |((((((X+transpose(X,4) ) +transpose(X,7) ) +transpose(X,7) ) +transpose((transpose(shuffle(X) ,-5) +transpose(transpose(X,-7) ,7) ) ,7) ) +transpose((((transpose(X,-7) +transpose(shuffle(X) ,12) ) +transpose(transpose((X+X) ,-7) ,4) ) +transpose(((((X+transpose(X,4) ) +transpose(X,7) ) +transpose((echo(X,4,6) +transpose(transpose(X,4) ,12) ) ,4) ) +transpose(transpose(X,-5) ,7) ) ,7) ) ,12) ) |(arpeggio((step(shuffle(X) ,12) +transpose(step(((X+transpose(X,4) ) +transpose(X,7) ) ,12) ,7) ) ) +arpeggio(echo((transpose(X,-7) +transpose(X,12) ) ,4,6) ) ) ) ) ) ) ) ,-7) random seed used was 0 EXPR = arpeggio(((((echo(transpose((X+transpose(X,7) ) ,4) ,4,6) +transpose((((transpose(transpose(echo(((X+transpose(X,12) ) +transpose(arpeggio(X) ,12) ) ,4,6) ,-5) ,-7) +transpose(shuffle(step((X+transpose(echo(X,4,6) ,12) ) ,12) ) ,4) ) +transpose(((transpose(X,-7) +transpose(X,12) ) +transpose(arpeggio(shuffle(X) ) ,12) ) ,7) ) +transpose(transpose(((((shuffle(arpeggio(X) ) +transpose((((X+transpose(X,4) ) +transpose(X,7) ) +transpose(echo(X,4,6) ,7) ) ,4) ) +transpose(arpeggio((X+transpose(X,12) ) ) ,7) ) +transpose(transpose((X+X) ,4) ,7) ) |echo(transpose((X+transpose(X,7) ) ,-7) ,4,6) ) ,-5) ,12) ) ,12) ) |transpose(((arpeggio(shuffle(shuffle(transpose(echo(transpose(X,4) ,4,6) ,4) ) ) ) +transpose((((shuffle(shuffle((X+transpose(X,7) ) ) ) +transpose(transpose(step(X,12) ,-7) ,7) ) +transpose((((transpose(X,4) +transpose(echo(X,4,6) ,12) ) +transpose(echo(X,4,6) ,4) ) +transpose((X+((X+transpose(X,4) ) +transpose(X,7) ) ) ,7) ) ,12) ) +transpose((((X+transpose(((X+transpose(X,4) ) +transpose(X,7) ) ,7) ) +transpose((((((X+transpose(X,12) ) +transpose(X,4) ) +transpose(((X+transpose(X,4) ) +transpose(X,7) ) ,4) ) +transpose(shuffle(echo(X,4,6) ) ,7) ) +transpose(((echo(X,4,6) +transpose(((X+transpose((X+transpose(X,7) ) ,4) ) +transpose(X,7) ) ,4) ) +transpose(echo(((X+transpose(X,4) ) +transpose(X,7) ) ,4,6) ,7) ) ,7) ) ,4) ) +transpose(((shuffle(X) +transpose(((step(X,12) +transpose(shuffle(X) ,4) ) +transpose((X+transpose(X,7) ) ,7) ) ,12) ) |step(transpose(X,4) ,12) ) ,7) ) ,7) ) ,4) ) +transpose(((step(X,12) +X) +transpose(((X+transpose(X,12) ) +transpose(echo(X,4,6) ,7) ) ,7) ) ,7) ) ,-5) ) +transpose((arpeggio(transpose((arpeggio(X) +transpose(step(echo(X,4,6) ,12) ,12) ) ,4) ) +transpose((((shuffle((step(X,12) +transpose(X,12) ) ) +transpose(shuffle((step(X,12) +transpose(transpose(transpose((X+transpose(X,12) ) ,-7) ,-5) ,7) ) ) ,4) ) +transpose(((transpose(X,-7) +transpose(transpose(echo(X,4,6) ,4) ,12) ) +transpose(((shuffle(X) +transpose((X+transpose(X,12) ) ,7) ) +transpose(arpeggio(arpeggio(echo(X,4,6) ) ) ,12) ) ,12) ) ,7) ) |(((echo((X+transpose(step(transpose(X,4) ,12) ,12) ) ,4,6) +transpose(arpeggio(echo(X,4,6) ) ,4) ) +transpose(((echo((X+transpose(X,12) ) ,4,6) +transpose(((((transpose(X,4) +transpose(X,4) ) +transpose(((X+transpose(X,4) ) +transpose(X,7) ) ,7) ) +transpose(transpose(X,4) ,4) ) +transpose(((step(X,12) +transpose((X+transpose(X,12) ) ,4) ) +transpose(echo(X,4,6) ,7) ) ,7) ) ,4) ) +transpose(echo(transpose(transpose(X,-7) ,-7) ,4,6) ,7) ) ,7) ) |echo(((arpeggio(shuffle(X) ) +transpose(shuffle(X) ,12) ) +transpose((step(transpose(X,-5) ,12) +transpose((shuffle(X) +transpose(step(X,12) ,7) ) ,7) ) ,7) ) ,4,6) ) ) ,7) ) ,7) ) |((arpeggio((transpose(((((X+X) +transpose(transpose(transpose(X,-5) ,-7) ,4) ) +transpose((arpeggio(X) +transpose(X,12) ) ,7) ) +transpose(transpose(shuffle((X+transpose(X,7) ) ) ,4) ,7) ) ,4) +transpose((((echo(shuffle(X) ,4,6) +((transpose(X,-5) +transpose(transpose(X,-7) ,4) ) +transpose(X,7) ) ) +transpose((((X+transpose(X,4) ) +transpose(X,7) ) +transpose(shuffle(transpose((X|X) ,4) ) ,12) ) ,4) ) +transpose(echo((step((X+(X+transpose(X,7) ) ) ,12) +transpose((X|transpose(X,-7) ) ,7) ) ,4,6) ,7) ) ,12) ) ) +transpose(transpose(((transpose(arpeggio(transpose((X+transpose(X,12) ) ,-5) ) ,-7) +transpose(echo(((X+transpose(X,4) ) +transpose(X,7) ) ,4,6) ,4) ) +transpose((echo(((((X+transpose(X,4) ) +transpose(X,7) ) +transpose(X,4) ) +transpose(transpose(X,4) ,7) ) ,4,6) +transpose((((shuffle(X) +transpose(arpeggio(X) ,7) ) +transpose(step(X,12) ,7) ) |arpeggio(step(X,12) ) ) ,7) ) ,7) ) ,-7) ,12) ) +transpose(((((transpose((arpeggio(step(X,12) ) +transpose(transpose(X,-7) ,7) ) ,-5) |(shuffle(((X+(X|X) ) +transpose((((X+transpose(X,7) ) +transpose(X,4) ) +transpose(echo(X,4,6) ,7) ) ,7) ) ) +transpose(echo(transpose(shuffle(X) ,-5) ,4,6) ,7) ) ) |arpeggio((((((arpeggio(X) +transpose((((X+X) +transpose(step(X,12) ,4) ) +transpose((X+X) ,7) ) ,12) ) +transpose(transpose(transpose(X,-5) ,4) ,4) ) +transpose(transpose(echo(X,4,6) ,4) ,7) ) +transpose(shuffle(((transpose(X,-7) +transpose(transpose(transpose(X,4) ,4) ,4) ) +transpose((((X+transpose(X,7) ) +transpose(transpose(X,-5) ,12) ) |transpose(X,-7) ) ,7) ) ) ,7) ) +transpose(transpose(transpose(transpose(X,-7) ,-7) ,-5) ,7) ) ) ) +transpose(arpeggio(echo(transpose(X,-7) ,4,6) ) ,12) ) |step(((transpose(X,-7) +transpose(((echo(X,4,6) +echo(X,4,6) ) +transpose(shuffle(X) ,12) ) ,12) ) +transpose(step(shuffle(X) ,12) ,12) ) ,12) ) ,12) ) ) ) random seed used was 0

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