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:
((step(transpose((step((shuffle((step(transpose(X,-7) ,12) +transpose(arpeggio(X) ,12) ) ) |(step(step(((X+transpose(X,4) ) +transpose(X,7) ) ,12) ,12) +echo((transpose(X,4) +transpose(arpeggio(X) ,12) ) ,4,6) ) ) ,12) +transpose(transpose(((((X+transpose(X,4) ) +transpose(X,7) ) |X) +transpose(transpose(X,-5) ,12) ) ,4) ,-5) ) ,4) ,12) +transpose(((arpeggio((step((arpeggio(echo(arpeggio(((transpose((shuffle((X|X) ) |((X+X) +transpose(X,7) ) ) ,4) +transpose(transpose(((transpose(shuffle((shuffle(X) +transpose(transpose(X,-5) ,7) ) ) ,-5) +transpose(((transpose(shuffle((X|X) ) ,-5) +transpose((X|X) ,4) ) +transpose(((((X|X) +transpose(X,4) ) +transpose(X,7) ) +transpose(shuffle(echo(X,4,6) ) ,7) ) ,7) ) ,4) ) +transpose(echo(transpose(arpeggio(X) ,4) ,4,6) ,7) ) ,-5) ,4) ) +transpose(shuffle(((shuffle(X) +step(shuffle(X) ,12) ) +transpose(((X|(X+X) ) +transpose(X,12) ) ,12) ) ) ,7) ) ) ,4,6) ) +transpose(shuffle((shuffle(transpose((arpeggio(echo(step((X+transpose((X+transpose(X,12) ) ,12) ) ,12) ,4,6) ) +transpose(echo(transpose(echo(transpose(X,4) ,4,6) ,4) ,4,6) ,7) ) ,-5) ) |transpose(shuffle((((echo(X,4,6) +(X|X) ) +transpose(arpeggio(arpeggio(arpeggio(X) ) ) ,4) ) +transpose((step((X+transpose(X,7) ) ,12) +transpose(transpose(X,4) ,12) ) ,7) ) ) ,-5) ) ) ,12) ) ,12) +transpose(((transpose(step(((((transpose(transpose(transpose(X,-5) ,4) ,-5) +transpose((((transpose((shuffle(X) +transpose(shuffle(X) ,7) ) ,4) |arpeggio(X) ) |transpose((arpeggio(((X+transpose(X,4) ) +transpose(X,7) ) ) |(transpose(transpose(X,-7) ,4) +transpose(X,12) ) ) ,-5) ) +transpose(((transpose(transpose(X,-7) ,4) +step(((shuffle(X) +transpose(X,4) ) +transpose(echo(X,4,6) ,7) ) ,12) ) |step((shuffle(X) |step(X,12) ) ,12) ) ,7) ) ,4) ) +transpose((((X+transpose(transpose((shuffle(X) +(X|X) ) ,-7) ,4) ) +transpose(echo(((X+X) |arpeggio(X) ) ,4,6) ,7) ) |arpeggio(arpeggio(transpose(transpose(X,-7) ,-5) ) ) ) ,7) ) |transpose(shuffle(transpose(echo((X+transpose(X,12) ) ,4,6) ,-7) ) ,-7) ) |transpose(((step(shuffle(X) ,12) +transpose((transpose(transpose(X,4) ,4) +(((transpose(X,-7) +(X+X) ) +transpose(((X+transpose(X,4) ) +transpose(X,7) ) ,4) ) +transpose(X,7) ) ) ,12) ) +(transpose(transpose(echo(X,4,6) ,-5) ,4) |arpeggio(echo(X,4,6) ) ) ) ,-5) ) ,12) ,4) +transpose(step(((arpeggio(((((X+transpose(X,7) ) +transpose(transpose(X,4) ,4) ) +transpose(echo(X,4,6) ,7) ) +transpose(X,12) ) ) |transpose(transpose((X+transpose(transpose(X,-7) ,-7) ) ,-7) ,-7) ) +transpose(transpose((arpeggio(X) +transpose((echo(X,4,6) +transpose(((X+X) |X) ,7) ) ,7) ) ,-5) ,7) ) ,12) ,-5) ) |arpeggio(transpose(transpose(transpose(arpeggio((((transpose(transpose((X+transpose(X,12) ) ,4) ,-7) +transpose((X|X) ,4) ) +transpose(arpeggio(X) ,7) ) +transpose(shuffle((((X+transpose(X,7) ) |X) |(X+X) ) ) ,7) ) ) ,-5) ,-5) ,-5) ) ) ,7) ) ) +transpose(transpose(echo(arpeggio(echo(shuffle(transpose(((step(X,12) +arpeggio(X) ) +transpose(X,12) ) ,-5) ) ,4,6) ) ,4,6) ,-5) ,12) ) +transpose(((arpeggio(step((transpose(echo(shuffle(((echo(transpose(X,-5) ,4,6) +transpose(echo(X,4,6) ,12) ) |transpose(((((X|X) +transpose(X,4) ) +transpose((X+X) ,7) ) +transpose(shuffle(X) ,7) ) ,-5) ) ) ,4,6) ,-5) +transpose(transpose(transpose(transpose(transpose(X,4) ,-5) ,-5) ,-5) ,-7) ) ,12) ) +transpose(shuffle(echo(((((transpose(transpose((shuffle(arpeggio(X) ) +X) ,4) ,4) +transpose(step((transpose(transpose(((step(X,12) +transpose(X,4) ) +transpose(shuffle(X) ,7) ) ,4) ,4) +transpose((transpose(X,-7) +(X|(X+transpose(X,7) ) ) ) ,12) ) ,12) ,4) ) +transpose(arpeggio((((((X+transpose(X,4) ) +transpose(X,7) ) +transpose(X,4) ) +transpose(echo(X,4,6) ,7) ) +transpose(arpeggio((X+transpose(X,12) ) ) ,12) ) ) ,7) ) +transpose(arpeggio(shuffle((((transpose(echo(X,4,6) ,-5) +transpose(transpose((X+transpose(X,12) ) ,-7) ,4) ) +transpose(arpeggio(X) ,7) ) +transpose(transpose(arpeggio(X) ,4) ,12) ) ) ) ,-5) ) |(((((transpose(((shuffle(((echo(X,4,6) +arpeggio(X) ) +transpose(shuffle(transpose(X,-5) ) ,7) ) ) +transpose((transpose(shuffle(X) ,-5) +transpose(step(((X+transpose(X,4) ) +transpose(X,7) ) ,12) ,7) ) ,4) ) +transpose((((((X+echo(X,4,6) ) +transpose(X,4) ) +transpose((X|X) ,7) ) +(X+transpose(X,12) ) ) |echo(transpose(arpeggio(X) ,-5) ,4,6) ) ,7) ) ,-7) +transpose(transpose(arpeggio((step(transpose(X,4) ,12) +transpose((X+transpose(X,12) ) ,12) ) ) ,4) ,4) ) +transpose(echo(shuffle((shuffle(X) |X) ) ,4,6) ,7) ) +transpose(echo(shuffle(((step(X,12) +transpose((arpeggio(X) +transpose(shuffle(transpose(X,-7) ) ,12) ) ,4) ) +transpose(step(transpose(echo(X,4,6) ,4) ,12) ,7) ) ) ,4,6) ,4) ) +transpose(step(((shuffle(X) +echo(((shuffle(transpose(X,4) ) +transpose(((X|X) +X) ,4) ) +transpose(arpeggio(((X+X) +transpose(X,7) ) ) ,7) ) ,4,6) ) |transpose(transpose(X,4) ,-5) ) ,12) ,7) ) +shuffle(transpose((transpose(arpeggio(transpose(transpose(X,-5) ,4) ) ,-7) +transpose((transpose(transpose(transpose(X,4) ,-7) ,-7) +(transpose(((X+X) +transpose(X,12) ) ,-7) +transpose((transpose(X,-7) |(X|((X+transpose(X,4) ) +transpose(X,7) ) ) ) ,12) ) ) ,12) ) ,4) ) ) ) ,4,6) ) ,12) ) +shuffle(((transpose(step(transpose(transpose((arpeggio((X+transpose(X,7) ) ) +transpose(arpeggio(step(transpose(((X+X) +transpose((X+(X|X) ) ,12) ) ,-5) ,12) ) ,7) ) ,-7) ,-7) ,12) ,-7) +transpose(transpose(((shuffle((shuffle(transpose(X,-7) ) |shuffle(X) ) ) +transpose(arpeggio((transpose((X+(X+transpose(X,7) ) ) ,-5) +transpose((transpose(transpose(X,-7) ,4) +transpose(shuffle(arpeggio(X) ) ,12) ) ,7) ) ) ,7) ) +arpeggio(transpose(((transpose(X,-7) |transpose(transpose(X,-5) ,4) ) +transpose(transpose(X,-7) ,12) ) ,-5) ) ) ,-5) ,4) ) +transpose(shuffle((((((transpose(step(echo(X,4,6) ,12) ,-7) |step(transpose(arpeggio(X) ,-7) ,12) ) +transpose(transpose(transpose(transpose(transpose(transpose(X,4) ,-5) ,-7) ,-7) ,4) ,4) ) +transpose((transpose(transpose(arpeggio(((((step(X,12) +transpose(transpose(echo(X,4,6) ,-5) ,4) ) +transpose((X|step(X,12) ) ,7) ) |((X+transpose(X,4) ) +transpose(X,7) ) ) +transpose(transpose(shuffle(X) ,-5) ,7) ) ) ,4) ,-5) +transpose((((transpose(transpose(transpose(shuffle(transpose(X,4) ) ,4) ,4) ,-5) +transpose(echo(((arpeggio(transpose(X,-5) ) +transpose(shuffle(X) ,4) ) +transpose(transpose(step(X,12) ,-5) ,7) ) ,4,6) ,12) ) +transpose((transpose(transpose(arpeggio(((X|X) +(X+X) ) ) ,4) ,4) +transpose((((((((X+X) +transpose(((X+transpose(X,4) ) +transpose(X,7) ) ,12) ) +transpose(X,4) ) +transpose(transpose(X,4) ,7) ) +transpose(shuffle((arpeggio(X) +transpose(X,-7) ) ) ,4) ) +transpose(echo((arpeggio(X) |transpose(X,4) ) ,4,6) ,7) ) +transpose(arpeggio(X) ,-7) ) ,7) ) ,4) ) +transpose((shuffle(transpose(transpose((X+X) ,-5) ,-5) ) +((transpose(arpeggio(transpose(X,4) ) ,4) +transpose(transpose(((step(step(X,12) ,12) +transpose((((X+transpose(transpose(X,-5) ,12) ) +transpose(transpose(X,-5) ,4) ) +transpose(arpeggio(X) ,7) ) ,4) ) +transpose(shuffle(step(X,12) ) ,7) ) ,-5) ,4) ) +transpose(shuffle(arpeggio((X|X) ) ) ,7) ) ) ,7) ) ,12) ) ,7) ) +transpose((((transpose(((arpeggio((X+transpose(X,12) ) ) +transpose(transpose(X,-7) ,4) ) +transpose(X,7) ) ,-5) +transpose((arpeggio(((X+X) +transpose(X,7) ) ) |((transpose(X,-7) |X) |(X+transpose(transpose(X,4) ,7) ) ) ) ,4) ) +transpose((transpose(transpose(transpose(transpose(X,4) ,-5) ,4) ,4) +(transpose(X,4) |shuffle(step(X,12) ) ) ) ,7) ) +transpose(transpose((transpose((((X|transpose(X,-5) ) +transpose((X+X) ,4) ) +transpose((arpeggio(X) +transpose(arpeggio(echo(X,4,6) ) ,7) ) ,7) ) ,-5) +transpose(transpose((((X+transpose(X,4) ) +transpose(X,7) ) |(X+X) ) ,-7) ,-5) ) ,-7) ,7) ) ,12) ) +transpose(((transpose(shuffle((((((X|X) +transpose(shuffle(X) ,4) ) +transpose(transpose(transpose(transpose(X,4) ,-5) ,-7) ,7) ) +transpose(transpose(X,4) ,4) ) +transpose((echo(echo(X,4,6) ,4,6) +transpose(transpose(X,-5) ,7) ) ,7) ) ) ,-7) +transpose(echo(arpeggio(echo(X,4,6) ) ,4,6) ,7) ) |transpose(arpeggio((transpose(transpose(shuffle(shuffle(arpeggio(X) ) ) ,4) ,-5) +transpose(transpose(echo(transpose((shuffle(X) +X) ,-7) ,4,6) ,-7) ,7) ) ) ,4) ) ,-7) ) ) ,7) ) ) ) ,12) ) ,4) ) +transpose((arpeggio(arpeggio((((step(echo(arpeggio(shuffle((transpose(shuffle(X) ,4) +transpose(echo(shuffle(((X+transpose(X,4) ) +transpose(X,7) ) ) ,4,6) ,7) ) ) ) ,4,6) ,12) +transpose(echo(transpose(transpose(shuffle(((arpeggio(X) +X) |arpeggio(X) ) ) ,-7) ,4) ,4,6) ,4) ) +transpose(((((echo(((shuffle(X) |(arpeggio(echo(step(X,12) ,4,6) ) |echo(X,4,6) ) ) |arpeggio((X+X) ) ) ,4,6) +((transpose(((transpose(X,4) +transpose(transpose(((X+transpose(X,12) ) +transpose(transpose(X,-7) ,7) ) ,4) ,4) ) +transpose(shuffle((transpose(X,4) +transpose(arpeggio(X) ,7) ) ) ,7) ) ,-7) +transpose(shuffle(((X+transpose(X,7) ) |X) ) ,4) ) +transpose(arpeggio((shuffle((X|X) ) |echo((X+transpose(X,7) ) ,4,6) ) ) ,7) ) ) |(shuffle(((((step((X+transpose(transpose(X,-7) ,7) ) ,12) +(transpose(shuffle(X) ,4) +step(transpose(X,-7) ,12) ) ) +transpose((transpose((transpose(X,-7) |(X+arpeggio(X) ) ) ,4) +transpose(arpeggio((X|arpeggio(X) ) ) ,12) ) ,4) ) +transpose((shuffle(shuffle(X) ) |(((X+transpose(X,4) ) +transpose(X,7) ) +(X+transpose(X,12) ) ) ) ,7) ) +transpose(arpeggio(step(arpeggio(step(X,12) ) ,12) ) ,7) ) ) +transpose(echo(step(transpose(transpose(shuffle(X) ,4) ,-5) ,12) ,4,6) ,7) ) ) +transpose(arpeggio(((((((shuffle(arpeggio((X+transpose(X,12) ) ) ) +(transpose(shuffle(X) ,-7) +transpose((echo(arpeggio(X) ,4,6) |transpose((X+transpose(X,12) ) ,-5) ) ,7) ) ) +transpose(transpose(arpeggio(step(X,12) ) ,4) ,-5) ) +transpose((transpose(arpeggio(X) ,4) |transpose((step(((X+transpose(echo(X,4,6) ,4) ) +transpose(transpose(X,-5) ,7) ) ,12) +(shuffle(transpose(X,4) ) +transpose((X+X) ,7) ) ) ,4) ) ,4) ) +transpose(shuffle((step(shuffle(transpose((arpeggio(X) |X) ,-5) ) ,12) |((((X+transpose(X,-5) ) +transpose((arpeggio(step(X,12) ) |((X|X) +X) ) ,7) ) +transpose(transpose(arpeggio(X) ,4) ,4) ) +transpose((((echo(X,4,6) +(X+X) ) |step(X,12) ) +shuffle(shuffle(shuffle(X) ) ) ) ,7) ) ) ) ,7) ) |((transpose(transpose(transpose(X,-5) ,-7) ,-5) |shuffle(arpeggio(X) ) ) +transpose(((transpose(X,-7) +shuffle(X) ) |X) ,-7) ) ) +transpose((((shuffle((X|echo(X,4,6) ) ) +transpose(((X+transpose(transpose(X,4) ,12) ) +transpose((X|X) ,7) ) ,4) ) +transpose((((X+transpose(X,7) ) +transpose(X,4) ) +transpose(X,7) ) ,7) ) +transpose(arpeggio(((X|X) +transpose(((X+transpose(X,4) ) +transpose(X,7) ) ,12) ) ) ,12) ) ,7) ) ) ,4) ) +transpose((transpose(transpose(X,-7) ,-5) +step(transpose(transpose((X+transpose((X+transpose(X,12) ) ,12) ) ,-7) ,-7) ,12) ) ,7) ) ,7) ) +transpose(transpose((((transpose(transpose(transpose(((X+transpose(X,12) ) +transpose(X,7) ) ,-5) ,-5) ,4) +transpose(transpose(arpeggio(transpose(((transpose(X,-5) +transpose(arpeggio(X) ,4) ) +transpose(X,7) ) ,4) ) ,-5) ,4) ) +transpose(echo((step(shuffle(X) ,12) |step(echo(transpose(X,-7) ,4,6) ,12) ) ,4,6) ,7) ) +arpeggio((transpose(echo(arpeggio((arpeggio(((X+X) +transpose(X,7) ) ) +transpose(step((shuffle(X) +(X|X) ) ,12) ,12) ) ) ,4,6) ,-5) +transpose((arpeggio(echo(shuffle((((X+transpose(shuffle(X) ,7) ) +transpose((arpeggio(X) |X) ,4) ) +transpose(arpeggio(transpose(X,-7) ) ,7) ) ) ,4,6) ) +echo((((X|transpose(X,-7) ) +(X|shuffle(X) ) ) |shuffle(arpeggio(X) ) ) ,4,6) ) ,12) ) ) ) ,4) ,7) ) ) ) |(arpeggio((((step(arpeggio(transpose((((arpeggio((X+transpose(((X+transpose(X,4) ) +transpose(X,7) ) ,12) ) ) +transpose(transpose(shuffle(X) ,4) ,7) ) +transpose(((X|X) +transpose(transpose(X,-7) ,12) ) ,-7) ) +(((arpeggio(transpose(X,-5) ) |((X+transpose(X,4) ) +transpose(X,7) ) ) |transpose(shuffle(arpeggio(X) ) ,-5) ) +transpose(((arpeggio((X+transpose(X,12) ) ) +transpose((X+transpose((X+transpose(X,7) ) ,4) ) ,4) ) +transpose(step(shuffle((X+X) ) ,12) ,7) ) ,12) ) ) ,4) ) ,12) +transpose(((transpose(step(transpose(echo(X,4,6) ,4) ,12) ,-7) +transpose(echo(shuffle((arpeggio(X) +(X+arpeggio(X) ) ) ) ,4,6) ,4) ) +transpose(shuffle(((arpeggio(transpose(shuffle((X+X) ) ,-5) ) +transpose(transpose((X+transpose(transpose((X+X) ,-7) ,7) ) ,4) ,4) ) +transpose((step(X,12) |(X+X) ) ,7) ) ) ,7) ) ,4) ) +((((transpose(((shuffle((shuffle(transpose((shuffle(X) |transpose((X|X) ,4) ) ,-7) ) |(((X|X) +transpose(((shuffle(step(X,12) ) +transpose((((X|X) +transpose((X+X) ,4) ) +transpose(transpose(X,-5) ,7) ) ,4) ) +transpose(transpose(X,-5) ,7) ) ,4) ) +transpose((transpose(transpose(X,-5) ,-7) +transpose(transpose(shuffle(X) ,4) ,7) ) ,7) ) ) ) |step((((transpose((X|X) ,-7) +transpose((((((X+transpose(transpose(transpose(X,4) ,-5) ,7) ) +transpose((echo((X+transpose(X,7) ) ,4,6) +(X+transpose(transpose(X,-5) ,7) ) ) ,4) ) +transpose(echo(echo((X|X) ,4,6) ,4,6) ,7) ) +transpose(transpose(X,4) ,4) ) +transpose((arpeggio(transpose(X,-5) ) +transpose(arpeggio(X) ,7) ) ,7) ) ,4) ) +transpose(transpose((transpose(X,4) +transpose(transpose(X,4) ,7) ) ,4) ,7) ) +((X+transpose(transpose(X,-5) ,7) ) +transpose(arpeggio(X) ,12) ) ) ,12) ) |shuffle(((shuffle(echo(X,4,6) ) +transpose(((((X+transpose(X,12) ) +shuffle(X) ) +transpose((transpose(X,-5) +transpose(arpeggio(X) ,12) ) ,4) ) +transpose(transpose(transpose(X,-7) ,-5) ,7) ) ,7) ) +transpose(transpose((echo(X,4,6) +transpose((arpeggio((X+X) ) |arpeggio(step(X,12) ) ) ,7) ) ,-5) ,-7) ) ) ) ,-5) +transpose(transpose(transpose(step(transpose(shuffle(transpose((((transpose(X,-5) |X) |step(transpose(X,-7) ,12) ) |transpose(X,-7) ) ,-5) ) ,-5) ,12) ,-7) ,4) ,12) ) +transpose(shuffle((arpeggio(transpose((transpose((shuffle(shuffle(step(X,12) ) ) |(((X+transpose(X,7) ) +arpeggio(transpose(X,4) ) ) +transpose(step(transpose(X,4) ,12) ,12) ) ) ,-7) |transpose(shuffle(echo(arpeggio(X) ,4,6) ) ,4) ) ,4) ) |shuffle((transpose(transpose(shuffle(X) ,4) ,-7) |transpose(shuffle(shuffle((arpeggio(X) +shuffle(X) ) ) ) ,-5) ) ) ) ) ,4) ) +transpose((arpeggio(arpeggio(arpeggio(arpeggio((shuffle((X+transpose(transpose(X,-5) ,-5) ) ) |echo(step(echo((step(shuffle(X) ,12) +arpeggio(X) ) ,4,6) ,12) ,4,6) ) ) ) ) ) +transpose((transpose(transpose(transpose(shuffle((shuffle(((X+X) +(shuffle(X) +transpose(shuffle(X) ,7) ) ) ) |(transpose((X|(X+transpose(X,7) ) ) ,4) +transpose(shuffle(transpose(shuffle(X) ,-7) ) ,7) ) ) ) ,-5) ,4) ,-7) |transpose(((transpose((transpose(X,4) |(X+(X+transpose(X,7) ) ) ) ,4) +transpose(((X+transpose(transpose(X,4) ,12) ) |transpose(step(shuffle(X) ,12) ,4) ) ,4) ) +transpose(((arpeggio(echo(X,4,6) ) +transpose((echo(transpose(X,4) ,4,6) +shuffle(X) ) ,12) ) +transpose((X+transpose(X,12) ) ,12) ) ,7) ) ,-7) ) ,7) ) ,7) ) +transpose((((echo(arpeggio((transpose(transpose(X,-7) ,4) |transpose(echo((X+transpose(X,7) ) ,4,6) ,-5) ) ) ,4,6) |(((((((echo(X,4,6) +transpose((X+transpose(X,7) ) ,4) ) +transpose(transpose(X,-7) ,7) ) +transpose((transpose(X,-5) +step(X,12) ) ,7) ) +transpose(step((X+arpeggio(transpose((X+X) ,4) ) ) ,12) ,12) ) +transpose(transpose(shuffle(shuffle((X|X) ) ) ,-5) ,4) ) +transpose(arpeggio((echo(X,4,6) +(shuffle(X) +transpose(X,12) ) ) ) ,7) ) |((shuffle(transpose(step(transpose(transpose(X,4) ,-7) ,12) ,-7) ) +transpose(transpose((shuffle(X) |transpose(X,-5) ) ,4) ,12) ) +shuffle((((step(X,12) |(step(transpose(X,-7) ,12) +transpose(arpeggio(transpose(X,-7) ) ,7) ) ) +transpose(transpose((shuffle(X) +transpose(step(X,12) ,7) ) ,-7) ,4) ) +transpose(transpose(X,4) ,7) ) ) ) ) ) +transpose(step(transpose(arpeggio(step((transpose((step(shuffle(X) ,12) +(X|echo(X,4,6) ) ) ,-5) |(transpose(transpose((X+transpose(X,7) ) ,4) ,-5) +transpose((X+X) ,-7) ) ) ,12) ) ,4) ,12) ,4) ) +transpose(transpose(arpeggio((arpeggio(transpose(step(X,12) ,-5) ) +transpose((transpose(transpose(echo(X,4,6) ,4) ,4) +transpose(shuffle(transpose(((shuffle(((X+transpose(X,4) ) +transpose(X,7) ) ) +transpose((arpeggio(X) +transpose((X+transpose(X,7) ) ,7) ) ,4) ) +transpose(shuffle((X|X) ) ,7) ) ,-5) ) ,12) ) ,7) ) ) ,-7) ,7) ) ,12) ) ) |arpeggio((transpose(((transpose(((echo(echo(X,4,6) ,4,6) +transpose((transpose(shuffle((X+transpose(X,7) ) ) ,4) |arpeggio(arpeggio(X) ) ) ,12) ) +arpeggio(arpeggio(arpeggio((X|X) ) ) ) ) ,-5) +transpose(echo(transpose(arpeggio((arpeggio(transpose(transpose(X,-5) ,-5) ) +X) ) ,-7) ,4,6) ,4) ) +transpose(((transpose((transpose(((X+X) +transpose(transpose(X,-7) ,7) ) ,-5) +transpose(transpose((((transpose(X,4) +transpose(step(X,12) ,4) ) +transpose(X,7) ) +arpeggio(X) ) ,-7) ,12) ) ,4) |((transpose(X,-5) +(echo(X,4,6) +transpose(X,12) ) ) |(echo((step(X,12) +transpose((X+X) ,12) ) ,4,6) +transpose(transpose(echo(X,4,6) ,4) ,12) ) ) ) +transpose((transpose(((transpose((X+transpose(shuffle(X) ,12) ) ,-5) +transpose((X+transpose(X,7) ) ,7) ) +(arpeggio(X) +transpose(X,4) ) ) ,4) +transpose(transpose((step(transpose(X,4) ,12) +transpose(X,4) ) ,-7) ,12) ) ,12) ) ,7) ) ,-7) +transpose((shuffle((arpeggio(arpeggio(transpose(arpeggio(transpose((X+X) ,-7) ) ,4) ) ) +(shuffle(step(shuffle((X|X) ) ,12) ) +transpose(arpeggio((((arpeggio(X) +X) +transpose(transpose(X,-5) ,4) ) +transpose(echo((X+transpose(X,7) ) ,4,6) ,7) ) ) ,12) ) ) ) |transpose((((transpose(((X+transpose(X,4) ) +transpose(X,7) ) ,-7) +(X+transpose(X,12) ) ) |(transpose(transpose(X,-5) ,-5) +transpose(transpose(X,-5) ,12) ) ) +transpose(shuffle((X+transpose(X,7) ) ) ,4) ) ,4) ) ,12) ) ) ) ) +transpose(shuffle(arpeggio(arpeggio(transpose(transpose(((shuffle(transpose(((shuffle((X|X) ) +transpose(X,4) ) +transpose(X,7) ) ,4) ) +transpose((transpose(echo(echo(X,4,6) ,4,6) ,4) +((X+X) +transpose(X,12) ) ) ,12) ) +(transpose((transpose((transpose(X,-5) +transpose((X+(X+transpose(X,12) ) ) ,7) ) ,4) |(arpeggio((X+X) ) |transpose(X,-5) ) ) ,-7) |(((transpose((X|X) ,4) |(X+transpose(X,-5) ) ) |shuffle(((transpose(X,4) +transpose(shuffle(step(X,12) ) ,4) ) +transpose(transpose(X,4) ,7) ) ) ) +transpose(arpeggio(transpose((X+transpose(transpose(X,-5) ,12) ) ,-5) ) ,7) ) ) ) ,4) ,-7) ) ) ) ,12) ) ) ,7) )
random seed used was 248310337

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