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:
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Phrase for X:
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After 20 generations the expression "X" became this:
(((((arpeggio((echo(arpeggio((((echo((transpose(X,-5) +step(transpose(X,-5) ,12) ) ,4,6) +transpose(transpose(transpose(transpose((step(((shuffle(X) +transpose(X,4) ) +transpose(transpose(X,-5) ,7) ) ,12) +transpose((X|(X+transpose(X,12) ) ) ,-5) ) ,4) ,4) ,4) ,4) ) +transpose(transpose(transpose((transpose(transpose((X+transpose(X,4) ) ,4) ,-5) |arpeggio((X+arpeggio(X) ) ) ) ,-7) ,-7) ,7) ) +transpose(((((transpose(X,-7) +transpose((X+(X+X) ) ,7) ) +transpose(transpose(((X+transpose(X,12) ) |X) ,-7) ,7) ) |(transpose((X|X) ,4) +((transpose(X,-5) +transpose(X,4) ) +transpose((((X+transpose(X,4) ) +transpose(X,7) ) +transpose(transpose(X,4) ,12) ) ,7) ) ) ) +((X|X) +transpose(arpeggio(X) ,12) ) ) ,12) ) ) ,4,6) +transpose(shuffle(((((transpose(step(X,12) ,-5) +transpose(shuffle((transpose(X,-7) |(X|X) ) ) ,7) ) |transpose(step(((X|(X+X) ) +transpose(transpose(step(X,12) ,4) ,7) ) ,12) ,-5) ) +(((((((arpeggio(X) +transpose(X,7) ) +transpose(step(shuffle(X) ,12) ,4) ) +transpose(((transpose(X,-5) +transpose(X,4) ) +transpose((transpose(X,4) +transpose(transpose(X,4) ,7) ) ,7) ) ,7) ) +transpose(transpose(transpose(X,4) ,-7) ,4) ) +transpose(((X+X) +(((X+transpose(X,4) ) +transpose(X,7) ) +X) ) ,7) ) +transpose((transpose(X,-7) +transpose(X,4) ) ,-5) ) |(transpose((transpose(X,-7) +arpeggio(X) ) ,-5) +transpose(arpeggio(transpose(transpose(X,-5) ,-5) ) ,-5) ) ) ) +transpose((transpose(((transpose(X,4) |transpose((X+X) ,4) ) +step(step((X+X) ,12) ,12) ) ,-7) +transpose(((transpose((X+transpose(X,12) ) ,-5) +transpose(transpose(transpose(X,4) ,4) ,7) ) +(shuffle(((X+X) |step((shuffle(X) |(X+X) ) ,12) ) ) +transpose(step(((X+transpose((X|X) ,7) ) +(echo(X,4,6) |transpose(X,-5) ) ) ,12) ,12) ) ) ,7) ) ,-5) ) ) ,7) ) ) +transpose((transpose(transpose(arpeggio(step(((step(transpose(X,4) ,12) +transpose(transpose((X+transpose(X,12) ) ,4) ,12) ) +shuffle(transpose(X,-5) ) ) ,12) ) ,4) ,4) +transpose(step(transpose(shuffle(transpose(step(X,12) ,-5) ) ,-7) ,12) ,12) ) ,-7) ) +((transpose(step((shuffle(transpose((X+transpose(shuffle(step((X|X) ,12) ) ,7) ) ,-5) ) +transpose(transpose(echo(((X+transpose(transpose(transpose(X,4) ,4) ,4) ) |(transpose(echo((transpose(X,-5) +transpose(X,-5) ) ,4,6) ,-7) |((X+(X+transpose(X,7) ) ) +transpose(transpose(X,-5) ,12) ) ) ) ,4,6) ,-7) ,7) ) ,12) ,-5) +transpose(echo((((arpeggio(((((((transpose(X,-7) |X) +transpose(step((X+transpose(X,7) ) ,12) ,7) ) +transpose((X+(transpose(X,-5) +(X+X) ) ) ,12) ) +transpose(step(echo(X,4,6) ,12) ,7) ) +transpose((((((X|X) +transpose(X,7) ) |transpose(transpose(transpose(X,-5) ,4) ,4) ) +transpose((echo(transpose(X,-7) ,4,6) +transpose(arpeggio(X) ,7) ) ,4) ) +transpose(echo(((transpose(step(X,12) ,4) +transpose((X+((X+X) +transpose(X,7) ) ) ,4) ) +transpose((transpose(X,4) +transpose((X+transpose(X,12) ) ,7) ) ,7) ) ,4,6) ,7) ) ,4) ) +transpose(step(((arpeggio((X|X) ) |transpose(X,-7) ) |transpose(echo(transpose(X,-7) ,4,6) ,4) ) ,12) ,7) ) ) +transpose((step((step(transpose(echo(X,4,6) ,4) ,12) +arpeggio(arpeggio((X+transpose(X,12) ) ) ) ) ,12) +transpose(((transpose(arpeggio(transpose(X,-5) ) ,-5) +transpose(transpose((transpose((X|X) ,-5) +transpose((shuffle(X) +X) ,7) ) ,4) ,12) ) +((((X+transpose((X+transpose(X,12) ) ,7) ) +transpose(transpose((X+X) ,4) ,4) ) +transpose(step(transpose(transpose(X,-7) ,4) ,12) ,7) ) +((((X+X) +transpose((((X+X) +(X+transpose(X,12) ) ) +(X+transpose(X,7) ) ) ,4) ) +transpose(echo(((X+transpose(X,12) ) +X) ,4,6) ,7) ) |(transpose(X,-5) |echo(shuffle(X) ,4,6) ) ) ) ) ,12) ) ,7) ) +transpose((((transpose(((X|X) +echo(echo(X,4,6) ,4,6) ) ,-5) +((transpose((transpose((X+X) ,4) +transpose(arpeggio(X) ,4) ) ,-5) |(step(step(X,12) ,12) +transpose(transpose(transpose(X,4) ,-5) ,-7) ) ) +transpose(step((X+transpose(X,12) ) ,12) ,12) ) ) +transpose((((transpose(X,4) |(transpose((X+transpose(X,7) ) ,-5) |arpeggio(X) ) ) |transpose(transpose(X,-7) ,-5) ) +transpose(transpose((transpose(((X+transpose(X,4) ) +transpose(X,7) ) ,-7) +transpose((shuffle((X+transpose(X,12) ) ) +X) ,7) ) ,-5) ,12) ) ,12) ) |(transpose(transpose(transpose(X,-7) ,-5) ,-7) +transpose((transpose(((X+transpose(step(X,12) ,12) ) +transpose(transpose((X+X) ,-7) ,12) ) ,-7) |transpose(shuffle((X|X) ) ,-7) ) ,12) ) ) ,12) ) |transpose(arpeggio(((echo(transpose(X,-7) ,4,6) +transpose(((echo(X,4,6) +transpose(((X+transpose(X,7) ) |(X+X) ) ,7) ) |((echo(transpose(X,-7) ,4,6) +transpose(((X+transpose(X,7) ) +(X+transpose(X,7) ) ) ,4) ) +transpose(echo((X+transpose(X,12) ) ,4,6) ,7) ) ) ,4) ) +transpose(transpose(transpose(transpose(arpeggio(X) ,-5) ,-5) ,-7) ,7) ) ) ,4) ) ,4,6) ,4) ) +transpose((((transpose((transpose(echo(echo(X,4,6) ,4,6) ,-7) +shuffle(arpeggio(transpose(transpose(X,-7) ,4) ) ) ) ,-5) +transpose((((((((transpose((X+transpose(X,12) ) ,-5) +transpose((X+step((X+X) ,12) ) ,4) ) +transpose(step((X+transpose(X,12) ) ,12) ,7) ) +transpose((((((X|transpose(X,-7) ) +transpose(((X+transpose((X|X) ,4) ) +transpose(X,7) ) ,7) ) +((transpose(shuffle(((X+transpose(X,7) ) +transpose(X,12) ) ) ,-7) +transpose(((X+transpose(X,12) ) +transpose(((X+transpose(arpeggio(X) ,4) ) +transpose(X,7) ) ,12) ) ,4) ) +transpose(((((X+transpose(X,4) ) +transpose(X,7) ) |transpose(X,-7) ) +(transpose(echo(X,4,6) ,-5) |transpose(shuffle(X) ,-7) ) ) ,7) ) ) +transpose(transpose(transpose((arpeggio(X) +(X|((X+transpose(X,4) ) +transpose(X,7) ) ) ) ,-7) ,4) ,4) ) +transpose(transpose((X|(transpose(X,-5) +transpose(X,12) ) ) ,4) ,7) ) ,4) ) +transpose((transpose(transpose(arpeggio(transpose(X,-7) ) ,-7) ,-7) |transpose(transpose(X,-5) ,4) ) ,7) ) |shuffle(transpose(transpose(echo(transpose(transpose(transpose(X,-5) ,4) ,4) ,4,6) ,-5) ,-7) ) ) +transpose(transpose(transpose(transpose((echo(X,4,6) |(((transpose(X,-7) |X) +transpose(((echo(X,4,6) +transpose(X,12) ) |(X+(X+X) ) ) ,4) ) +transpose((transpose(X,-7) +X) ,7) ) ) ,4) ,4) ,-5) ,4) ) +transpose(((((((shuffle((X|X) ) |(X|X) ) +transpose((X|X) ,7) ) +((transpose(X,4) |shuffle(X) ) |transpose(shuffle(X) ,-5) ) ) +transpose((step(X,12) |((X+transpose((X+transpose(X,12) ) ,7) ) +transpose(transpose(X,-7) ,12) ) ) ,7) ) +transpose((transpose((transpose(transpose(arpeggio((X+X) ) ,-5) ,4) +transpose(transpose(step((X+transpose(X,12) ) ,12) ,-7) ,12) ) ,4) +transpose(((echo(shuffle(echo(X,4,6) ) ,4,6) +((arpeggio(transpose(X,-5) ) +transpose(echo((X+X) ,4,6) ,4) ) +transpose((((X+transpose(X,7) ) |X) +transpose(X,-7) ) ,7) ) ) +transpose(((arpeggio(arpeggio(X) ) +transpose(transpose(X,-7) ,4) ) +transpose(((X+transpose(X,12) ) |((X+transpose(X,4) ) +transpose(X,7) ) ) ,7) ) ,12) ) ,12) ) ,7) ) +arpeggio((shuffle(transpose(X,-7) ) +transpose(arpeggio(transpose((X+transpose(X,-5) ) ,-5) ) ,12) ) ) ) ,7) ) ,7) ) +transpose(shuffle(arpeggio(step((transpose((X+transpose(shuffle(X) ,7) ) ,-7) |(echo(((X+transpose(X,4) ) +transpose(X,7) ) ,4,6) +(transpose((X+X) ,-5) +transpose(transpose(X,-5) ,4) ) ) ) ,12) ) ) ,7) ) +(arpeggio(arpeggio(transpose((((((((X+transpose(X,4) ) +transpose(X,7) ) +(X+transpose(X,12) ) ) |shuffle((transpose(X,-7) |X) ) ) +transpose((((X+transpose(X,7) ) +transpose((X+X) ,7) ) +X) ,7) ) +step((X+transpose((X|(X+transpose(X,7) ) ) ,7) ) ,12) ) |shuffle((((transpose(transpose(X,4) ,-7) +transpose(step(X,12) ,12) ) +transpose(((transpose(X,4) +transpose(transpose(X,-5) ,4) ) +transpose((X|(X|X) ) ,7) ) ,12) ) +(((X+transpose(X,4) ) +transpose(transpose(X,-7) ,7) ) +(((X+X) +transpose(transpose(X,4) ,12) ) +transpose(X,7) ) ) ) ) ) ,-7) ) ) |shuffle(shuffle(transpose((((shuffle(X) +transpose(echo(X,4,6) ,4) ) +transpose(shuffle(X) ,7) ) +transpose(echo((X+X) ,4,6) ,12) ) ,-7) ) ) ) ) ,7) ) ) +transpose(transpose((((transpose(transpose(((((X|echo(((X+transpose(X,4) ) +transpose(X,7) ) ,4,6) ) +step((shuffle(X) |transpose(X,-5) ) ,12) ) +transpose(step(transpose(echo((((X+transpose(X,4) ) +transpose(X,7) ) +X) ,4,6) ,-7) ,12) ,12) ) +transpose(transpose(transpose(shuffle(transpose(X,4) ) ,-5) ,-7) ,12) ) ,-5) ,-5) +transpose(transpose(transpose(((echo((((((((((X+transpose(X,12) ) +shuffle(X) ) +transpose(transpose((X+transpose(X,7) ) ,4) ,4) ) +transpose(((X+transpose(X,12) ) +transpose(transpose(transpose(X,-7) ,-5) ,7) ) ,7) ) +transpose(transpose(transpose(transpose(X,-7) ,-7) ,-7) ,4) ) +transpose(transpose((transpose(X,4) +transpose((X+X) ,12) ) ,-7) ,7) ) +transpose(transpose(transpose(shuffle((X+transpose(X,12) ) ) ,-7) ,-5) ,4) ) +transpose(shuffle((X|X) ) ,7) ) |((transpose(transpose(X,-7) ,4) |transpose(transpose(X,-5) ,-5) ) +step(shuffle(X) ,12) ) ) ,4,6) |transpose((step(((X+transpose(X,12) ) |(transpose(X,-5) +transpose((((X+transpose(X,12) ) +transpose(step(X,12) ,4) ) +transpose(transpose(X,-7) ,7) ) ,12) ) ) ,12) +(transpose(step((X+X) ,12) ,-7) +transpose(transpose(X,4) ,12) ) ) ,-5) ) +(((transpose(echo((X|X) ,4,6) ,-7) +transpose(arpeggio(((echo(X,4,6) |X) +transpose(transpose(transpose(X,-5) ,-5) ,7) ) ) ,4) ) +transpose(echo(X,4,6) ,7) ) +transpose(((transpose(((shuffle(((shuffle(X) +transpose(X,7) ) +transpose(X,7) ) ) +transpose(arpeggio(arpeggio((X+transpose((X+transpose(X,12) ) ,12) ) ) ) ,4) ) +transpose((shuffle(transpose(X,-5) ) |X) ,7) ) ,4) +transpose((transpose(transpose(X,-5) ,4) +step(transpose(X,-5) ,12) ) ,4) ) +transpose(transpose(step(transpose(step(X,12) ,-5) ,12) ,-5) ,7) ) ,7) ) ) ,4) ,-7) ,4) ) +transpose((((((((transpose((X+X) ,-7) +transpose((((X+transpose(echo(X,4,6) ,12) ) +transpose((X+X) ,4) ) +transpose(arpeggio(X) ,7) ) ,4) ) +((transpose(echo(X,4,6) ,-7) +(((X+transpose(X,4) ) +transpose((X|X) ,7) ) |(((X+transpose(X,7) ) +transpose(X,4) ) +transpose(X,7) ) ) ) +echo(echo(transpose((X|X) ,-5) ,4,6) ,4,6) ) ) +transpose(arpeggio(echo((arpeggio(X) +(step(X,12) |(X|X) ) ) ,4,6) ) ,4) ) +transpose(transpose(((echo(X,4,6) +transpose((((transpose(X,4) +X) +transpose(transpose(X,4) ,4) ) +transpose(X,7) ) ,12) ) +transpose(transpose(transpose(X,-7) ,-7) ,12) ) ,-7) ,7) ) +transpose(transpose(arpeggio((step(echo(X,4,6) ,12) |transpose((X+transpose(X,7) ) ,-5) ) ) ,-7) ,-7) ) +transpose(transpose(transpose(shuffle((arpeggio(step(X,12) ) +transpose(transpose(transpose(((X+transpose(X,4) ) +transpose(X,7) ) ,4) ,-7) ,7) ) ) ,-7) ,-5) ,12) ) +transpose(transpose(transpose(shuffle((transpose(X,4) +transpose(echo(X,4,6) ,12) ) ) ,4) ,-5) ,4) ) ,7) ) +(((echo(((transpose(shuffle(X) ,-5) +transpose(transpose(transpose(X,4) ,4) ,7) ) +transpose(arpeggio(transpose(transpose(transpose(((X+transpose((X|X) ,7) ) +echo(X,4,6) ) ,-7) ,4) ,-5) ) ,7) ) ,4,6) +transpose((transpose(shuffle(transpose(transpose(((X|X) |X) ,4) ,-7) ) ,-5) +transpose((step(arpeggio(transpose((arpeggio(X) |transpose(X,-7) ) ,4) ) ,12) +transpose((((transpose(X,4) +transpose((X|X) ,7) ) |((X+X) +transpose(X,7) ) ) +transpose((echo(((((X+transpose(X,7) ) |(X+transpose(X,12) ) ) +transpose(shuffle(step(X,12) ) ,12) ) +transpose((X+X) ,12) ) ,4,6) +transpose((((X+transpose(X,-5) ) +transpose(((X+transpose(X,4) ) +transpose(X,7) ) ,7) ) +transpose(shuffle(transpose(X,4) ) ,-5) ) ,12) ) ,12) ) ,7) ) ,7) ) ,12) ) |transpose(arpeggio(step((((shuffle((echo(X,4,6) +(X+transpose(echo(((X+transpose(X,4) ) +transpose(X,7) ) ,4,6) ,7) ) ) ) +transpose((transpose(arpeggio((X+transpose(X,12) ) ) ,-5) +transpose((((((X+transpose(X,12) ) +transpose(X,7) ) +transpose(((arpeggio(X) |arpeggio(X) ) +transpose((((X|X) +transpose(transpose(X,4) ,4) ) +transpose(transpose(X,-7) ,7) ) ,7) ) ,4) ) +transpose((X|step(X,12) ) ,7) ) |arpeggio(X) ) ,7) ) ,12) ) +transpose(step((shuffle((transpose(transpose(X,-5) ,4) +transpose(transpose(transpose(X,-5) ,4) ,7) ) ) +transpose(transpose((shuffle(X) |X) ,-7) ,7) ) ,12) ,7) ) |step(transpose((transpose(transpose(((X+transpose(X,7) ) +transpose(X,12) ) ,-5) ,-7) +transpose((((X|step(X,12) ) +transpose((step(transpose(X,-7) ,12) +transpose(transpose(X,-5) ,7) ) ,4) ) +transpose(transpose(X,-5) ,7) ) ,12) ) ,-5) ,12) ) ,12) ) ,4) ) +transpose(transpose(((echo(((echo((transpose(((X|X) +transpose(transpose(X,-7) ,12) ) ,-7) +arpeggio((X+X) ) ) ,4,6) +transpose(step(shuffle(((((((X+transpose((X+transpose(X,12) ) ,4) ) +transpose((X|X) ,7) ) +transpose(transpose(transpose(X,4) ,4) ,12) ) +shuffle(X) ) +transpose(((transpose(X,4) +X) +((X+X) +transpose(step(X,12) ,12) ) ) ,4) ) +transpose(echo(echo(X,4,6) ,4,6) ,7) ) ) ,12) ,12) ) +transpose(transpose(transpose(transpose((echo(arpeggio(X) ,4,6) +transpose(X,4) ) ,-7) ,4) ,4) ,7) ) ,4,6) +transpose(echo(((((((transpose((X|X) ,4) +transpose(transpose(arpeggio((X+X) ) ,-7) ,4) ) +transpose(echo(transpose(X,4) ,4,6) ,7) ) |transpose(transpose(transpose((X|X) ,-5) ,-7) ,-5) ) +(((transpose(X,4) +transpose(X,7) ) +transpose(X,7) ) |transpose((X|X) ,4) ) ) |transpose(transpose(transpose(transpose(X,-5) ,-7) ,-7) ,-5) ) +transpose(((arpeggio(transpose(X,-5) ) |step(X,12) ) +transpose((transpose(step((echo(X,4,6) +(transpose(X,-5) +X) ) ,12) ,-5) +transpose((transpose(echo((X+transpose(X,12) ) ,4,6) ,4) |((X|X) +transpose(transpose(X,-7) ,12) ) ) ,12) ) ,7) ) ,7) ) ,4,6) ,4) ) +transpose(arpeggio(echo(echo(transpose((arpeggio(transpose(transpose((transpose(X,4) |arpeggio(X) ) ,-5) ,4) ) +transpose((transpose(X,-5) +transpose(transpose((X+transpose(X,12) ) ,4) ,12) ) ,12) ) ,4) ,4,6) ,4,6) ) ,7) ) ,-5) ,4) ) ) ,-7) ,4) ) +transpose(transpose(transpose((echo(shuffle(shuffle(arpeggio((((((X|(transpose(X,-7) +transpose(X,4) ) ) +transpose(arpeggio((X+transpose(X,12) ) ) ,4) ) +transpose((step(X,12) +transpose((X+(X+transpose(X,7) ) ) ,12) ) ,7) ) +(echo((X|X) ,4,6) |(X+transpose(step(transpose(X,-5) ,12) ,12) ) ) ) +transpose(((echo(step(transpose(X,4) ,12) ,4,6) +transpose((transpose(((X+transpose(X,4) ) +transpose(X,7) ) ,-5) +transpose((X+transpose((X|X) ,7) ) ,-5) ) ,12) ) +transpose(transpose(((X|X) +transpose(transpose(X,4) ,12) ) ,-7) ,12) ) ,7) ) ) ) ) ,4,6) +transpose(transpose((shuffle((echo(transpose(transpose((X+transpose((X+transpose(X,12) ) ,7) ) ,-7) ,-5) ,4,6) |(echo(step(transpose((X+X) ,-7) ,12) ,4,6) +shuffle(((((((X+transpose(X,12) ) +shuffle(X) ) +transpose((X+X) ,4) ) +transpose(step(X,12) ,7) ) +transpose(((X|X) |echo(X,4,6) ) ,4) ) +transpose(step(X,12) ,7) ) ) ) ) ) |arpeggio((transpose(transpose(X,4) ,4) +transpose(arpeggio((transpose(((X+transpose(X,12) ) |X) ,4) +transpose(((transpose(X,-5) +transpose(X,4) ) +transpose(shuffle(X) ,7) ) ,7) ) ) ,12) ) ) ) ,-5) ,7) ) ,4) ,4) ,7) ) +transpose((echo(transpose(((echo(((shuffle(transpose(((X+transpose((X+X) ,4) ) +transpose(arpeggio(X) ,7) ) ,-7) ) +transpose(transpose(shuffle(transpose((X+transpose(X,7) ) ,-5) ) ,4) ,4) ) +transpose(transpose(echo(((X+transpose(transpose(X,4) ,4) ) +transpose((X|X) ,7) ) ,4,6) ,-5) ,7) ) ,4,6) +transpose(arpeggio(step((((transpose(((X+transpose(X,12) ) |transpose(X,4) ) ,4) +(transpose(X,4) +transpose(shuffle(X) ,4) ) ) +transpose(transpose(((step((step(X,12) |X) ,12) +transpose(X,12) ) |(shuffle(X) +(((X+transpose(X,7) ) |transpose(X,-7) ) |transpose(X,-7) ) ) ) ,4) ,4) ) +transpose(((transpose(arpeggio(X) ,4) |((((transpose(transpose(X,4) ,-5) +transpose(transpose(X,-5) ,4) ) +transpose(((X|X) |echo(X,4,6) ) ,7) ) +echo((transpose(X,4) +shuffle(X) ) ,4,6) ) +transpose(step(X,12) ,12) ) ) |transpose((step(X,12) |shuffle(arpeggio(transpose(X,-7) ) ) ) ,-5) ) ,7) ) ,12) ) ,4) ) +transpose(transpose((((transpose((shuffle(transpose(X,-5) ) |X) ,4) |(((transpose(X,4) +transpose(X,4) ) +transpose(transpose(shuffle(transpose(X,-5) ) ,-7) ,7) ) |X) ) |((transpose(transpose(((X+transpose(X,7) ) +transpose(X,12) ) ,-5) ,4) +transpose(arpeggio(transpose((X+X) ,4) ) ,4) ) +transpose((transpose((X|X) ,-7) |(X|X) ) ,7) ) ) +transpose(((shuffle(transpose(X,4) ) +transpose(transpose((transpose((X+transpose(X,12) ) ,-7) +transpose(X,12) ) ,-5) ,12) ) |((transpose((X|X) ,4) +transpose(transpose(X,4) ,4) ) +transpose((X|X) ,7) ) ) ,4) ) ,-7) ,7) ) ,4) ,4,6) |((transpose(((transpose(((echo(shuffle(transpose((arpeggio(transpose(X,-7) ) +transpose((arpeggio(X) +transpose(X,-7) ) ,12) ) ,4) ) ,4,6) +transpose(shuffle((arpeggio(((X+X) +transpose(step(X,12) ,12) ) ) +transpose(arpeggio((X+transpose(X,7) ) ) ,12) ) ) ,4) ) +transpose(transpose(((X+(X+transpose(X,7) ) ) +((transpose(transpose(X,4) ,-5) +transpose(arpeggio(transpose(X,4) ) ,4) ) +transpose(step(transpose(arpeggio(X) ,-5) ,12) ,7) ) ) ,4) ,7) ) ,-5) +transpose(transpose(transpose(transpose(transpose(step((X+X) ,12) ,-7) ,-5) ,4) ,-5) ,4) ) +transpose(transpose(transpose((((echo(X,4,6) +transpose(transpose(((X+transpose(X,4) ) +transpose(X,7) ) ,-5) ,4) ) +transpose(arpeggio(transpose(X,4) ) ,7) ) +transpose(X,4) ) ,-7) ,4) ,7) ) ,-7) +transpose(((((transpose(transpose(((transpose(X,4) +(X+X) ) +(X+transpose((transpose(X,-7) |X) ,12) ) ) ,4) ,-5) +transpose((((shuffle(echo(transpose(((X+transpose(X,4) ) +transpose(X,7) ) ,-7) ,4,6) ) +transpose(((((step(step(echo(X,4,6) ,12) ,12) +transpose((transpose(X,-5) |transpose(X,4) ) ,4) ) +transpose((step(X,12) |(transpose(X,-5) +transpose(arpeggio(X) ,7) ) ) ,7) ) +transpose(transpose(transpose((X+transpose(((X+transpose(X,4) ) +transpose(X,7) ) ,12) ) ,4) ,4) ,4) ) +transpose((step(X,12) +transpose(((X+transpose(X,12) ) |(X+X) ) ,7) ) ,7) ) ,12) ) +transpose((echo((((echo((X+transpose(X,7) ) ,4,6) +transpose(echo(transpose(X,4) ,4,6) ,12) ) |((X+X) +transpose(X,7) ) ) +transpose(transpose(transpose(X,-7) ,4) ,7) ) ,4,6) +transpose(step(((arpeggio(transpose(echo(X,4,6) ,-5) ) +transpose(arpeggio(step((X+transpose((X+X) ,7) ) ,12) ) ,4) ) +transpose(transpose(((X|X) +((X+transpose(X,4) ) +transpose(X,7) ) ) ,4) ,7) ) ,12) ,12) ) ,7) ) +(((transpose((transpose(transpose(((X+transpose(X,12) ) +(X+X) ) ,4) ,-7) +(((X+X) +transpose((((X+X) +transpose((X+transpose(X,12) ) ,4) ) +transpose(X,7) ) ,7) ) +((transpose(X,-7) +transpose(transpose(X,-7) ,4) ) +transpose((X|X) ,7) ) ) ) ,-7) +transpose(((transpose(arpeggio(transpose(X,4) ) ,4) +transpose(shuffle(arpeggio(X) ) ,12) ) +transpose(shuffle((X+arpeggio(X) ) ) ,7) ) ,4) ) +transpose(transpose(((X+transpose(X,12) ) +transpose(arpeggio(X) ,7) ) ,4) ,7) ) +(arpeggio(transpose(((X|X) +transpose((X+transpose(X,12) ) ,12) ) ,4) ) |((X+transpose(transpose(transpose((X|X) ,4) ,4) ,7) ) |transpose(transpose(echo((X|X) ,4,6) ,-5) ,-7) ) ) ) ) ,12) ) +transpose(((step(((X+transpose(X,12) ) +transpose(arpeggio(((X+transpose(X,4) ) +transpose(X,7) ) ) ,12) ) ,12) +transpose(shuffle(transpose((X+transpose(X,12) ) ,-7) ) ,7) ) +transpose(transpose((X+transpose(X,-5) ) ,-7) ,-5) ) ,-5) ) +transpose(echo(transpose(((transpose(X,4) +transpose(transpose(X,-7) ,7) ) |transpose(transpose(transpose(X,-7) ,-7) ,-5) ) ,4) ,4,6) ,4) ) +transpose(step((shuffle(transpose(step(((transpose(X,-5) +transpose((X+transpose(X,7) ) ,7) ) |(X+transpose(step(X,12) ,7) ) ) ,12) ,4) ) +transpose(transpose(transpose(transpose(((X+transpose(X,-5) ) +transpose(transpose(X,4) ,-7) ) ,4) ,4) ,4) ,12) ) ,12) ,7) ) ,7) ) |(((transpose(((transpose(step((((X+transpose(X,4) ) +transpose(transpose(X,-7) ,7) ) +transpose(X,12) ) ,12) ,4) +transpose((shuffle((X|X) ) |(X+transpose(step(X,12) ,12) ) ) ,4) ) +step(((transpose(transpose(X,4) ,-7) +transpose(transpose(X,-5) ,-5) ) +transpose(X,-7) ) ,12) ) ,4) +(arpeggio((((transpose(((X|X) +transpose((transpose(X,-7) +transpose(X,7) ) ,12) ) ,4) +transpose((transpose(transpose(X,4) ,4) +transpose(X,7) ) ,12) ) +transpose((((((X+transpose(X,4) ) +transpose(X,7) ) +(X+X) ) +transpose(transpose(X,-7) ,7) ) +transpose((transpose(step(X,12) ,4) +transpose(X,-7) ) ,7) ) ,4) ) +transpose(transpose(shuffle(transpose(transpose(transpose(X,-5) ,-5) ,4) ) ,-7) ,7) ) ) +transpose(transpose((((transpose(shuffle(transpose(X,4) ) ,4) +transpose((transpose(transpose(((X+X) |X) ,4) ,-5) +transpose(transpose(transpose(transpose(transpose(X,4) ,-7) ,-5) ,4) ,12) ) ,4) ) +transpose(echo(echo((transpose(X,-5) +transpose(arpeggio(X) ,12) ) ,4,6) ,4,6) ,7) ) +((transpose((echo(arpeggio(X) ,4,6) |shuffle(shuffle(X) ) ) ,-7) +transpose(transpose((((X+transpose(X,7) ) |X) +((X+transpose(X,12) ) +transpose(X,7) ) ) ,-5) ,4) ) +transpose(transpose((X|X) ,-5) ,7) ) ) ,-7) ,7) ) ) +((transpose(transpose(((((X+transpose((X|X) ,4) ) +transpose(X,7) ) +transpose((echo(X,4,6) +transpose(X,12) ) ,4) ) +transpose(shuffle(X) ,7) ) ,-7) ,-5) |arpeggio(echo(((arpeggio((X+((X+transpose(X,4) ) +transpose(X,7) ) ) ) +transpose((transpose(X,4) |((X+transpose(X,4) ) +transpose(X,7) ) ) ,7) ) |(step(echo(X,4,6) ,12) +transpose(transpose(X,-7) ,7) ) ) ,4,6) ) ) +transpose((transpose((transpose(X,-5) |(X+X) ) ,-7) |transpose(transpose(echo(X,4,6) ,-5) ,4) ) ,12) ) ) +transpose(transpose((shuffle(((shuffle(step(X,12) ) +transpose((step((X|X) ,12) +transpose(((X|X) |transpose((X|(X|X) ) ,4) ) ,7) ) ,4) ) +transpose(transpose(((((X|transpose(X,-5) ) +transpose(X,12) ) +transpose(transpose(echo((X+transpose(X,7) ) ,4,6) ,-5) ,4) ) +transpose((((X|(X|X) ) +transpose(transpose(((X+transpose(X,4) ) +transpose(X,7) ) ,-5) ,4) ) +transpose((X+transpose((X|X) ,12) ) ,7) ) ,7) ) ,-7) ,7) ) ) +transpose((transpose((((transpose(((X+transpose(X,7) ) +((X+transpose(step(X,12) ,4) ) +transpose(transpose(X,4) ,7) ) ) ,4) +transpose(transpose(echo((X+transpose(X,12) ) ,4,6) ,-7) ,12) ) +transpose((((step(X,12) |((shuffle(X) +transpose(transpose(X,-7) ,4) ) +transpose(X,7) ) ) +transpose(transpose(X,-5) ,12) ) |(step(X,12) |X) ) ,4) ) +transpose(step(transpose(transpose(X,4) ,-5) ,12) ,7) ) ,-7) +transpose(echo((transpose((step(X,12) |((X+transpose(X,4) ) +transpose(X,7) ) ) ,-5) +((transpose(X,-7) +transpose(transpose((X+transpose(X,12) ) ,4) ,4) ) +transpose(echo(X,4,6) ,7) ) ) ,4,6) ,12) ) ,12) ) ,-7) ,12) ) ) ) ,7) )
random seed used was 97433831

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