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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After 20 generations the expression "X" became this:
((arpeggio(arpeggio((((shuffle(X) +transpose(step(X,12) ,12) ) |(((transpose(X,-5) +transpose(X,4) ) +transpose(arpeggio(X) ,7) ) +transpose(echo(X,4,6) ,12) ) ) |(arpeggio(((transpose(X,-5) +transpose(X,7) ) +((echo(X,4,6) |X) +(((X+transpose(transpose(X,-5) ,12) ) +transpose(shuffle(transpose(X,-7) ) ,7) ) +transpose(X,-7) ) ) ) ) +((shuffle(transpose((X+transpose(X,7) ) ,4) ) +((X|X) |arpeggio(X) ) ) +(transpose(transpose(X,-5) ,-5) |((transpose(X,4) +transpose(transpose(X,4) ,7) ) |transpose((X+transpose(X,7) ) ,-7) ) ) ) ) ) ) ) +((arpeggio((transpose(((transpose(transpose(transpose(step(X,12) ,4) ,-7) ,-7) +((transpose(step(transpose((arpeggio((((echo(X,4,6) +transpose(transpose(X,-5) ,4) ) +transpose((X|X) ,7) ) +X) ) |(((X+transpose(X,4) ) +transpose(X,7) ) |shuffle(X) ) ) ,4) ,12) ,4) +transpose(((transpose(step(transpose(X,-7) ,12) ,4) +transpose(echo(step(echo((X+transpose(X,7) ) ,4,6) ,12) ,4,6) ,4) ) +transpose(((((((arpeggio(X) +X) +step((X+transpose(X,12) ) ,12) ) +transpose(shuffle(X) ,4) ) +transpose(X,7) ) +transpose(transpose((transpose(X,4) +transpose(transpose(transpose(X,4) ,-5) ,7) ) ,4) ,12) ) +((X|X) +step(X,12) ) ) ,7) ) ,4) ) +transpose(transpose(transpose((step((echo(shuffle(X) ,4,6) +step(X,12) ) ,12) +step(arpeggio(((transpose(X,4) +X) +transpose(transpose((X+X) ,4) ,12) ) ) ,12) ) ,-5) ,-5) ,7) ) ) |(transpose((((transpose(transpose(step(X,12) ,-5) ,-5) |((X+transpose((X+X) ,7) ) |echo(X,4,6) ) ) +((((transpose(transpose(arpeggio(arpeggio(X) ) ,-7) ,4) +transpose(transpose(shuffle(transpose(transpose(X,-5) ,-7) ) ,-7) ,4) ) +transpose((((((X|X) +transpose(shuffle(shuffle(X) ) ,4) ) +transpose(step(X,12) ,7) ) +transpose((X+transpose(X,12) ) ,4) ) +transpose(echo(X,4,6) ,7) ) ,7) ) +transpose(transpose((((X+transpose(X,12) ) +transpose((X+transpose(X,7) ) ,12) ) |transpose(X,-7) ) ,-5) ,4) ) +transpose((step(step((transpose(X,-7) +transpose((X+X) ,7) ) ,12) ,12) |(transpose(X,4) +transpose(step((shuffle(X) +transpose(X,12) ) ,12) ,7) ) ) ,7) ) ) |arpeggio(step(transpose(transpose(transpose(X,-7) ,4) ,4) ,12) ) ) ,4) |(((((((X+transpose(transpose(X,-5) ,4) ) +transpose(X,7) ) +transpose((X+transpose(X,12) ) ,7) ) |((echo(X,4,6) +transpose((X+transpose(X,12) ) ,12) ) +X) ) |transpose(transpose((echo(X,4,6) +transpose(step(transpose((X+transpose((X+transpose(X,7) ) ,7) ) ,-7) ,12) ,7) ) ,-7) ,4) ) +transpose(((transpose(step((((X|X) +transpose(X,12) ) +transpose(X,7) ) ,12) ,-7) +((((shuffle((X+X) ) |arpeggio(((X+transpose(X,4) ) +transpose(X,7) ) ) ) +transpose(((X+X) +transpose(transpose(X,-7) ,7) ) ,7) ) +transpose((transpose(arpeggio(X) ,4) +echo(arpeggio(shuffle(X) ) ,4,6) ) ,7) ) +transpose((transpose((((X+X) +transpose(shuffle(X) ,4) ) +transpose(transpose(X,-7) ,7) ) ,-5) +transpose(((X+transpose(X,12) ) +transpose((X+X) ,4) ) ,7) ) ,7) ) ) |((transpose((X+transpose(X,7) ) ,4) +transpose(transpose(transpose(shuffle(X) ,4) ,4) ,7) ) +transpose(transpose(((shuffle(X) +transpose((X+X) ,4) ) +transpose(transpose(((X+transpose(X,4) ) +transpose(X,7) ) ,-5) ,7) ) ,4) ,12) ) ) ,4) ) +transpose(transpose((transpose(X,-7) +transpose((X|X) ,12) ) ,-5) ,7) ) ) ) ,4) +transpose(transpose((((transpose(transpose(arpeggio(X) ,-7) ,4) +transpose((((transpose(X,-7) +transpose(X,7) ) +step((X+transpose(X,12) ) ,12) ) +transpose(transpose(X,4) ,7) ) ,12) ) +transpose(step(transpose((step(((X+X) |X) ,12) +transpose(transpose(transpose((X+X) ,4) ,4) ,-5) ) ,-7) ,12) ,4) ) +transpose(((((shuffle(X) +transpose(((transpose(transpose(X,-5) ,-7) +((X|X) +transpose(X,-5) ) ) +transpose(X,7) ) ,7) ) +transpose(arpeggio(transpose(transpose(X,-7) ,-7) ) ,4) ) +transpose(step(((X+transpose(X,4) ) +transpose(X,7) ) ,12) ,7) ) |(arpeggio(((X|X) +transpose(X,4) ) ) +transpose(echo((shuffle(transpose(X,4) ) +transpose(transpose(X,-7) ,-7) ) ,4,6) ,7) ) ) ,7) ) ,4) ,12) ) ) |(((step(transpose(transpose((((X|X) +transpose((X+transpose(transpose(X,-7) ,12) ) ,7) ) |(transpose((X+X) ,4) +(X+transpose((echo(X,4,6) +X) ,7) ) ) ) ,-7) ,4) ,12) +transpose(step(transpose(((((shuffle(transpose(X,-7) ) +(transpose(X,-7) +transpose(arpeggio(X) ,12) ) ) +echo(X,4,6) ) +transpose(((((transpose(X,4) +echo((X|(X+transpose(X,7) ) ) ,4,6) ) +transpose(step(transpose((((X+transpose(X,4) ) +transpose(X,7) ) |shuffle(X) ) ,4) ,12) ,4) ) +transpose(transpose(((transpose(X,4) +transpose(X,4) ) +transpose(X,7) ) ,4) ,7) ) +transpose((echo(transpose(X,4) ,4,6) |echo(arpeggio(X) ,4,6) ) ,7) ) ,4) ) +transpose(transpose(transpose((transpose(X,-5) +transpose((transpose(transpose(X,4) ,4) +transpose((transpose(X,4) +transpose(step(X,12) ,12) ) ,12) ) ,7) ) ,-7) ,-5) ,7) ) ,-5) ,12) ,-7) ) +transpose((step(transpose(arpeggio(transpose((((X+transpose(X,7) ) +transpose(X,12) ) +transpose(shuffle(transpose((X+transpose(X,12) ) ,-7) ) ,-5) ) ,-5) ) ,4) ,12) +transpose(transpose((((transpose((transpose((X+X) ,-5) +transpose(transpose((X+X) ,4) ,7) ) ,-5) |transpose(transpose(X,-7) ,-5) ) +transpose(transpose(transpose(step((X|X) ,12) ,-7) ,-5) ,7) ) +transpose(((X+(((X+transpose(X,4) ) +transpose(X,7) ) |(transpose(X,-5) +echo(X,4,6) ) ) ) +transpose(((((((((X|X) +transpose(transpose(X,4) ,12) ) +transpose(((transpose(X,-7) +transpose(step(X,12) ,12) ) +step((X+X) ,12) ) ,4) ) +transpose((((transpose(X,-7) +transpose(transpose(X,-5) ,4) ) +transpose(transpose((X+transpose(X,12) ) ,-7) ,7) ) +(((X+X) +transpose(transpose(X,-7) ,4) ) +transpose((transpose(X,-5) +transpose(step(X,12) ,12) ) ,7) ) ) ,7) ) +(transpose(step(X,12) ,-5) +(X+X) ) ) +transpose((transpose((((X+transpose(X,12) ) +transpose(X,7) ) +arpeggio(X) ) ,4) +transpose((transpose(transpose(X,-5) ,-7) +(X+X) ) ,12) ) ,12) ) +transpose(echo((((step((X+transpose(X,12) ) ,12) |echo(X,4,6) ) +transpose(X,-5) ) +transpose(((X+X) |step(X,12) ) ,12) ) ,4,6) ,4) ) +transpose(step(arpeggio(step(transpose((echo(X,4,6) +transpose(X,7) ) ,-7) ,12) ) ,12) ,7) ) ,7) ) ,7) ) ,-7) ,7) ) ,4) ) +transpose((transpose((transpose(echo(((transpose(step(X,12) ,-5) +(transpose(X,4) +step(X,12) ) ) +transpose(arpeggio(((X+transpose(X,7) ) |arpeggio(X) ) ) ,12) ) ,4,6) ,-7) |step(shuffle(transpose(transpose(transpose(arpeggio(shuffle(shuffle(transpose(X,4) ) ) ) ,-7) ,-5) ,4) ) ,12) ) ,-7) +transpose((transpose(transpose(transpose(((transpose(shuffle((X|(X+transpose(X,7) ) ) ) ,-5) +transpose((((X+transpose(transpose(step(X,12) ,-5) ,7) ) +transpose(transpose(((((X+transpose(X,7) ) +transpose(transpose(X,4) ,4) ) +transpose(X,7) ) +echo(X,4,6) ) ,-7) ,7) ) +transpose(shuffle((((X|X) +transpose(transpose(transpose(X,4) ,-5) ,7) ) |(step(echo(shuffle(X) ,4,6) ,12) +transpose(X,7) ) ) ) ,7) ) ,4) ) +transpose((step(step(((X|X) +transpose(transpose(X,4) ,7) ) ,12) ,12) |shuffle(arpeggio((X+(X+transpose(X,12) ) ) ) ) ) ,7) ) ,4) ,-5) ,-5) +transpose(((arpeggio(((X+X) +transpose(((X|X) +X) ,12) ) ) |arpeggio((transpose(transpose(X,-7) ,-5) +transpose(transpose((step(X,12) |(X|X) ) ,-5) ,12) ) ) ) |transpose((transpose((((transpose(X,-5) |transpose(X,-5) ) |(X|(X+transpose(X,7) ) ) ) +transpose(((shuffle(X) +(X+transpose(X,7) ) ) +transpose(X,7) ) ,7) ) ,-5) +transpose(transpose(((step(transpose((X+transpose(X,12) ) ,-7) ,12) +transpose(transpose(transpose(shuffle(X) ,4) ,4) ,12) ) |((transpose(step(X,12) ,-5) +transpose((arpeggio(transpose(((X+transpose(X,4) ) +transpose(X,7) ) ,-5) ) +transpose((transpose(X,4) |(X+X) ) ,4) ) ,4) ) +transpose(step(X,12) ,7) ) ) ,-7) ,7) ) ,-7) ) ,-5) ) ,7) ) ,7) ) ) +transpose(echo((((transpose(((transpose((X+X) ,-7) +transpose(transpose((((((X+transpose(X,12) ) +step(transpose(X,-5) ,12) ) +transpose(X,12) ) |(step(((X+X) +transpose((X+transpose(X,12) ) ,12) ) ,12) +transpose((transpose((X|X) ,-7) +transpose(shuffle(transpose(X,-7) ) ,12) ) ,7) ) ) +transpose((transpose(echo((X+X) ,4,6) ,-7) |(echo(X,4,6) +transpose(X,-5) ) ) ,12) ) ,4) ,12) ) +transpose(transpose(echo(transpose((echo(X,4,6) +transpose(transpose(X,-7) ,12) ) ,-7) ,4,6) ,4) ,4) ) ,-7) +transpose(arpeggio((transpose(echo(arpeggio((transpose(transpose(transpose(X,-7) ,-7) ,-7) +transpose(((shuffle(X) +transpose((X|X) ,4) ) +transpose(X,7) ) ,12) ) ) ,4,6) ,4) |((((((transpose(X,-7) +transpose(X,7) ) |(X+transpose(X,12) ) ) +transpose(transpose(transpose(step((step(X,12) +transpose((X|X) ,7) ) ,12) ,-5) ,-7) ,12) ) +transpose(transpose((arpeggio(X) +transpose(echo(((X+X) +transpose(X,12) ) ,4,6) ,12) ) ,4) ,4) ) +transpose((arpeggio(transpose(((transpose(transpose(X,-7) ,-5) +transpose(transpose(X,-5) ,4) ) +transpose(X,7) ) ,-5) ) +transpose(transpose(X,-5) ,4) ) ,7) ) +((shuffle(echo(((shuffle(echo(X,4,6) ) +transpose(echo(((transpose(X,-7) +transpose(X,4) ) +transpose(((X+transpose(X,4) ) +transpose(X,7) ) ,7) ) ,4,6) ,4) ) +transpose((transpose(transpose(X,-7) ,4) +transpose(echo(transpose(X,-7) ,4,6) ,12) ) ,7) ) ,4,6) ) +transpose(((((echo(transpose(X,-5) ,4,6) +transpose(transpose((X+transpose(X,7) ) ,-5) ,4) ) +transpose(((X+X) +transpose(X,12) ) ,7) ) +transpose(transpose(echo(shuffle(X) ,4,6) ,-7) ,12) ) +transpose(transpose(step(((X+transpose(X,7) ) |transpose(X,-5) ) ,12) ,-5) ,-5) ) ,4) ) +transpose((transpose(X,-5) +transpose(arpeggio(X) ,-5) ) ,7) ) ) ) ) ,12) ) +transpose((((((transpose(X,4) +shuffle(shuffle(X) ) ) |(transpose(X,-5) |(step(X,12) +transpose(X,12) ) ) ) |arpeggio(transpose(X,-5) ) ) |(transpose(shuffle(echo(((arpeggio(X) +transpose(((X|X) |shuffle(X) ) ,7) ) |(X+transpose(X,12) ) ) ,4,6) ) ,4) +((shuffle(X) +transpose(echo(X,4,6) ,4) ) +step(arpeggio((arpeggio(X) +transpose(((X+transpose(X,4) ) +transpose(X,7) ) ,7) ) ) ,12) ) ) ) |(((arpeggio(arpeggio(transpose((echo(X,4,6) +(X|X) ) ,4) ) ) +(transpose(transpose(X,4) ,-5) +shuffle(X) ) ) +transpose((step(((transpose(transpose(transpose(X,-5) ,4) ,-7) +transpose(transpose(X,-7) ,12) ) +transpose(shuffle(transpose((X|X) ,4) ) ,12) ) ,12) +transpose((echo(step(((X+transpose(X,7) ) +transpose(arpeggio(transpose(X,4) ) ,12) ) ,12) ,4,6) +(transpose(((transpose(step(X,12) ,4) |echo(echo(X,4,6) ,4,6) ) +transpose((echo(X,4,6) |arpeggio((X+transpose(X,7) ) ) ) ,7) ) ,-7) +step(transpose(echo(shuffle((X+X) ) ,4,6) ,4) ,12) ) ) ,7) ) ,7) ) +transpose(arpeggio(((shuffle((arpeggio(X) |transpose(X,-7) ) ) +transpose(transpose(transpose((X|echo(X,4,6) ) ,-5) ,4) ,4) ) +transpose(((X+transpose(X,12) ) |echo(X,4,6) ) ,7) ) ) ,12) ) ) ,12) ) |step((transpose(step(step(echo(((arpeggio(echo(transpose(X,-5) ,4,6) ) +transpose(transpose((X+X) ,-7) ,4) ) +transpose(((transpose(shuffle(X) ,-5) +echo(X,4,6) ) +echo(transpose(X,4) ,4,6) ) ,7) ) ,4,6) ,12) ,12) ,4) |transpose((((transpose(transpose(X,-5) ,4) +transpose(((X|transpose((X|X) ,-7) ) +X) ,4) ) +transpose((echo(step(X,12) ,4,6) |((shuffle(X) +transpose((X+X) ,7) ) +((X+transpose(X,4) ) +transpose(X,7) ) ) ) ,7) ) |(step(X,12) +arpeggio(X) ) ) ,-5) ) ,12) ) ,4,6) ,7) ) ) +(transpose(transpose(step((((arpeggio(((((((((X+transpose(X,12) ) +transpose((X+transpose(X,12) ) ,7) ) +transpose(transpose(X,4) ,4) ) +transpose(transpose(X,-5) ,7) ) |shuffle(((X+transpose(transpose(X,-7) ,4) ) +transpose(X,7) ) ) ) +transpose(arpeggio(((transpose(X,-5) +transpose((X|X) ,-5) ) +transpose(((transpose((transpose(X,-7) +echo(X,4,6) ) ,-5) +transpose(transpose(transpose((X|X) ,4) ,4) ,4) ) +transpose((transpose(transpose(X,4) ,-7) +transpose((X+X) ,12) ) ,7) ) ,12) ) ) ,7) ) |step(step(X,12) ,12) ) +arpeggio(transpose((transpose(X,4) +transpose(echo(X,4,6) ,7) ) ,-5) ) ) ) +transpose(transpose((echo(((transpose(X,-5) +X) |(X+transpose(echo(X,4,6) ,12) ) ) ,4,6) +transpose((echo(arpeggio(X) ,4,6) +transpose(X,4) ) ,4) ) ,-7) ,4) ) +transpose(((transpose(transpose((transpose(arpeggio((X+transpose(X,7) ) ) ,-7) +step(transpose(shuffle(X) ,-5) ,12) ) ,4) ,-7) +transpose((transpose((((X+(X+X) ) |(shuffle(X) |X) ) |transpose((transpose(X,4) |(X+X) ) ,-5) ) ,-5) +transpose((transpose(((X|X) |transpose(step((X|X) ,12) ,-7) ) ,-5) +step(transpose((transpose(X,-5) |transpose(X,-5) ) ,-5) ,12) ) ,12) ) ,12) ) +(step(transpose(((X+transpose(X,4) ) +transpose((X+transpose(X,12) ) ,7) ) ,-7) ,12) +(((transpose(X,-7) +transpose(X,12) ) +transpose(((X|X) |transpose(X,-7) ) ,12) ) +transpose((step((shuffle(X) +transpose(X,-7) ) ,12) |echo(arpeggio(transpose(X,-7) ) ,4,6) ) ,7) ) ) ) ,7) ) |step(shuffle((step((step(X,12) +transpose(X,12) ) ,12) +transpose((X+transpose(X,7) ) ,12) ) ) ,12) ) ,12) ,4) ,-7) +((transpose(((transpose((arpeggio(step((step(transpose(X,-5) ,12) +transpose((X+X) ,-7) ) ,12) ) |transpose((transpose(((X+transpose(X,4) ) +transpose(step(X,12) ,7) ) ,-7) |((transpose((X|X) ,-7) |(transpose(transpose(X,-7) ,-5) +X) ) |(arpeggio(step(echo(X,4,6) ,12) ) +transpose(((X+X) +X) ,-5) ) ) ) ,-7) ) ,-5) +transpose(echo(shuffle(transpose(((transpose((((echo(X,4,6) +transpose(X,-7) ) |X) +X) ,-5) +transpose(transpose(((arpeggio(X) +transpose(X,4) ) |transpose(((X+transpose(X,4) ) +transpose(X,7) ) ,4) ) ,-5) ,4) ) +transpose(transpose(transpose(((X|X) +transpose(arpeggio(X) ,12) ) ,-7) ,-7) ,7) ) ,-5) ) ,4,6) ,7) ) +transpose(transpose(transpose(((step(((transpose(X,-5) +transpose(((transpose(X,-7) +transpose((X+X) ,4) ) +transpose((X+X) ,7) ) ,7) ) +(((((transpose(X,-7) |transpose(X,-5) ) +transpose(step(arpeggio(X) ,12) ,4) ) +transpose(X,7) ) +transpose(step((X+(X|X) ) ,12) ,4) ) +transpose(shuffle(X) ,7) ) ) ,12) +(shuffle((X+transpose((X+transpose(X,12) ) ,7) ) ) +transpose(transpose(arpeggio(X) ,-7) ,12) ) ) +transpose(((((echo((((X+transpose(X,4) ) +transpose(X,7) ) |X) ,4,6) |((step(X,12) +transpose(X,12) ) +transpose((shuffle(X) |transpose(X,4) ) ,7) ) ) |((((X+transpose(X,4) ) +transpose(X,7) ) |shuffle(X) ) |((X+transpose(transpose(X,4) ,4) ) +transpose(X,7) ) ) ) +transpose(transpose(transpose(X,4) ,-7) ,4) ) +transpose(shuffle(transpose(X,-5) ) ,7) ) ,12) ) ,-7) ,-5) ,12) ) ,-5) |transpose(((echo(echo((((arpeggio(X) +transpose(X,7) ) +transpose(transpose(transpose(X,4) ,4) ,7) ) +transpose(((X+arpeggio(X) ) +transpose(shuffle(X) ,12) ) ,7) ) ,4,6) ,4,6) +(((((shuffle(((((X+transpose(X,4) ) +transpose(X,7) ) +((X+transpose(X,4) ) +transpose(X,7) ) ) |transpose(transpose((X|X) ,4) ,4) ) ) +transpose((transpose(arpeggio((X+transpose((X+X) ,12) ) ) ,-5) +(transpose((X+(X+transpose(X,7) ) ) ,-5) |echo(step(transpose(X,-7) ,12) ,4,6) ) ) ,12) ) +transpose(((echo(transpose(((transpose(X,-5) +transpose(step(X,12) ,4) ) +transpose(transpose(((X+transpose(X,4) ) +transpose(X,7) ) ,-7) ,7) ) ,4) ,4,6) +transpose(transpose(arpeggio((X|transpose(X,4) ) ) ,-5) ,4) ) +transpose((((transpose((X+X) ,-7) +transpose(X,-5) ) +transpose((transpose((X+X) ,-5) |echo(X,4,6) ) ,7) ) +transpose((arpeggio((X+X) ) |(((X+transpose(X,7) ) +X) +transpose((X+X) ,12) ) ) ,12) ) ,7) ) ,7) ) |transpose(((X+transpose(X,12) ) +transpose(((transpose(X,-7) +transpose(((transpose((X+transpose(X,7) ) ,4) +transpose(((((echo(X,4,6) +transpose(transpose(X,4) ,4) ) +transpose(transpose(X,-7) ,7) ) +transpose(transpose(transpose(X,4) ,-5) ,12) ) +((X+X) +transpose(X,7) ) ) ,4) ) +transpose(shuffle((step((X+transpose(X,7) ) ,12) +transpose(transpose(X,4) ,12) ) ) ,7) ) ,4) ) +transpose(transpose((transpose(X,-7) |transpose(transpose(X,4) ,-7) ) ,-5) ,7) ) ,12) ) ,4) ) +transpose((shuffle(transpose(((arpeggio((transpose(X,-7) |(((X+transpose(X,4) ) +transpose(X,7) ) +((X+transpose(X,4) ) +transpose(X,7) ) ) ) ) |shuffle(arpeggio((X|(X|X) ) ) ) ) +transpose((shuffle(X) |X) ,12) ) ,4) ) +transpose(((((((shuffle(X) +transpose(shuffle(transpose(X,-5) ) ,7) ) +transpose(transpose(step(X,12) ,-7) ,7) ) +transpose((X+transpose(X,7) ) ,7) ) +transpose((step(shuffle(transpose(X,4) ) ,12) +(((X+transpose(X,12) ) |X) |transpose(transpose(X,-5) ,-7) ) ) ,12) ) +transpose(transpose((((((X+transpose(X,12) ) +transpose(X,12) ) +transpose(X,4) ) +transpose((X|X) ,7) ) |(transpose((X+transpose(X,7) ) ,-5) +transpose(echo(transpose(X,4) ,4,6) ,7) ) ) ,4) ,12) ) +transpose((transpose((X+transpose(transpose(X,-5) ,12) ) ,4) +(transpose((transpose(echo(shuffle(X) ,4,6) ,4) +transpose((transpose((X|arpeggio(X) ) ,-5) +transpose(echo(arpeggio(X) ,4,6) ,7) ) ,12) ) ,-7) +transpose((transpose((transpose(X,-5) |transpose(shuffle((X+transpose(X,12) ) ) ,-7) ) ,4) +(((transpose(X,-7) |transpose(X,-5) ) +transpose((transpose((shuffle(X) +transpose(transpose(((X+transpose(X,4) ) +transpose(X,7) ) ,-5) ,12) ) ,4) +transpose(X,4) ) ,4) ) +transpose(((transpose(X,-5) +((X+transpose(X,4) ) +transpose(X,7) ) ) +transpose(arpeggio((step(X,12) |(transpose(X,-5) +transpose(X,12) ) ) ) ,7) ) ,7) ) ) ,7) ) ) ,7) ) ,12) ) ,4) ) +transpose((echo(shuffle(transpose(((X|X) +X) ,4) ) ,4,6) +transpose((echo(((((transpose(X,4) +transpose(((((X|X) |X) +transpose((step(X,12) |X) ,4) ) +transpose(transpose(echo(X,4,6) ,-5) ,7) ) ,7) ) |(transpose(X,-7) |X) ) +transpose(shuffle(transpose((X+transpose(arpeggio(X) ,7) ) ,-7) ) ,7) ) +transpose((transpose(X,4) +transpose(transpose(((X+transpose((X+transpose(X,12) ) ,7) ) +transpose(X,-7) ) ,4) ,12) ) ,7) ) ,4,6) +transpose(((X+transpose((X|X) ,12) ) +arpeggio(step(shuffle(((X+transpose(X,4) ) +transpose(X,7) ) ) ,12) ) ) ,7) ) ,12) ) ,7) ) ) |transpose((((((((X+transpose(shuffle(X) ,7) ) +transpose((transpose(X,-7) |X) ,4) ) +transpose((transpose(X,4) +(X|X) ) ,7) ) |arpeggio(transpose(X,-7) ) ) +transpose((((X+X) |X) |transpose(X,-5) ) ,-5) ) +transpose(transpose(transpose(echo(X,4,6) ,-5) ,-5) ,-5) ) +transpose((echo(transpose((arpeggio(X) |transpose(X,4) ) ,-7) ,4,6) +transpose(transpose(shuffle(X) ,-5) ,7) ) ,12) ) ,4) ) ,4) ) +transpose((((transpose((transpose(transpose(shuffle((transpose((shuffle((X|X) ) +transpose(step(X,12) ,7) ) ,-7) +((shuffle((X+transpose(X,12) ) ) +(arpeggio(X) +transpose((X+X) ,12) ) ) +step(transpose(X,4) ,12) ) ) ) ,-5) ,4) +transpose(transpose(transpose(arpeggio(transpose(transpose((X+transpose(X,7) ) ,4) ,4) ) ,4) ,-5) ,7) ) ,4) +arpeggio(transpose(((echo(transpose((transpose(transpose((X+X) ,-7) ,-7) |((X+X) |(X|X) ) ) ,-7) ,4,6) +transpose(transpose(((step(shuffle(X) ,12) +transpose(arpeggio(X) ,4) ) +transpose(step(X,12) ,7) ) ,4) ,7) ) +(transpose((transpose((step(X,12) +transpose((transpose(X,-7) +transpose(X,-7) ) ,7) ) ,-5) +transpose(echo(transpose(X,-5) ,4,6) ,7) ) ,4) +((shuffle(((((X+X) +transpose((X+transpose(X,7) ) ,4) ) +transpose((X+transpose(step(X,12) ,12) ) ,7) ) |transpose(transpose((X+X) ,-5) ,-7) ) ) +transpose((transpose(X,-7) +transpose((echo(X,4,6) +X) ,12) ) ,4) ) +transpose(transpose((step(X,12) |echo((X|X) ,4,6) ) ,-7) ,7) ) ) ) ,-7) ) ) +transpose((echo(((echo(transpose(arpeggio((X+(X+transpose(X,12) ) ) ) ,-5) ,4,6) +transpose(transpose(transpose((X+X) ,4) ,4) ,-7) ) +transpose(arpeggio(((arpeggio((((transpose(X,-5) |(X+transpose(X,12) ) ) +transpose(transpose(X,-7) ,4) ) +transpose(X,7) ) ) +(transpose(((X+transpose(X,12) ) +(X+transpose(X,7) ) ) ,-7) +transpose(((arpeggio(X) +transpose(X,4) ) +transpose(X,7) ) ,7) ) ) +transpose((transpose(transpose(shuffle(transpose(X,4) ) ,4) ,-7) |(X+X) ) ,12) ) ) ,7) ) ,4,6) +echo(transpose(((transpose(transpose((((transpose(X,-7) +transpose((arpeggio(X) +transpose(X,7) ) ,7) ) +transpose(transpose((X+X) ,-5) ,12) ) +transpose(((X+transpose(transpose(X,4) ,12) ) +transpose(transpose(step(X,12) ,-7) ,-5) ) ,12) ) ,4) ,4) +transpose((arpeggio((transpose(((X+X) +transpose(X,7) ) ,-7) +transpose(transpose(arpeggio(X) ,-5) ,7) ) ) +transpose(transpose(((((transpose(X,-5) +transpose(transpose(X,-5) ,4) ) +transpose((shuffle(X) +transpose(X,7) ) ,7) ) |((X+transpose(X,4) ) +transpose(X,7) ) ) +transpose(((shuffle(X) |((X|X) +X) ) |shuffle(transpose(X,4) ) ) ,12) ) ,-7) ,7) ) ,4) ) +transpose(((arpeggio((transpose(transpose(X,4) ,-5) +(((X|X) +transpose(X,4) ) +transpose(X,7) ) ) ) |(arpeggio((X+transpose(X,7) ) ) |shuffle(X) ) ) +transpose(shuffle((X|(X+transpose(X,12) ) ) ) ,12) ) ,7) ) ,-7) ,4,6) ) ,7) ) +((transpose(transpose(arpeggio(((((((X|X) +transpose(((X+transpose(X,4) ) +transpose(X,7) ) ,7) ) +(shuffle((X+transpose(X,7) ) ) +transpose((X+transpose(X,12) ) ,7) ) ) +((X|(X+transpose(X,12) ) ) |echo(X,4,6) ) ) +transpose(transpose((X+transpose(X,7) ) ,4) ,4) ) +transpose((((((X|X) +transpose(((X+transpose(X,4) ) +transpose(X,7) ) ,12) ) +transpose((X+transpose(transpose(X,-7) ,12) ) ,12) ) |(shuffle(X) +X) ) +(transpose(step(X,12) ,4) +transpose(X,-5) ) ) ,7) ) ) ,4) ,-5) +transpose(transpose(shuffle((((step(transpose(((((X+transpose(X,4) ) +transpose(X,7) ) +transpose(X,-7) ) +(X|X) ) ,-5) ,12) |((X+transpose(echo((X+X) ,4,6) ,12) ) +(X+transpose(X,7) ) ) ) |(transpose((X|X) ,4) +transpose(transpose(transpose(transpose((X+transpose(X,7) ) ,-5) ,4) ,-7) ,12) ) ) |echo(transpose(transpose(((X+transpose(shuffle(X) ,4) ) +transpose((X+transpose(X,12) ) ,7) ) ,4) ,-5) ,4,6) ) ) ,-5) ,7) ) +arpeggio(echo(transpose((echo((((echo(X,4,6) |X) +transpose((((X|X) +(X+transpose(transpose(X,4) ,7) ) ) |(X+X) ) ,4) ) +transpose(echo(arpeggio(X) ,4,6) ,7) ) ,4,6) +transpose(transpose(step((X+transpose(X,7) ) ,12) ,4) ,12) ) ,4) ,4,6) ) ) ) ,12) ) ) )
random seed used was 140200204

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