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:
(((transpose((((((transpose((((step(X,12) +X) +transpose(X,-7) ) +transpose(shuffle((transpose((X|X) ,4) +transpose((echo(X,4,6) |arpeggio(X) ) ,-5) ) ) ,7) ) ,-5) |transpose(transpose((((((shuffle(X) +shuffle(X) ) +transpose((X+transpose(X,7) ) ,4) ) +transpose(((X+transpose(X,12) ) +transpose((X+X) ,12) ) ,7) ) +((X+transpose(X,7) ) +transpose((X+transpose(X,7) ) ,12) ) ) +transpose(transpose((X+transpose(X,7) ) ,4) ,4) ) ,4) ,-7) ) +transpose((transpose(transpose(transpose(((((echo(X,4,6) +transpose(step(X,12) ,12) ) +transpose(transpose((echo(X,4,6) |X) ,-7) ,4) ) +transpose(X,7) ) +arpeggio(X) ) ,-7) ,4) ,-7) +transpose((((transpose(((transpose((transpose(X,4) |X) ,4) |(X+transpose(X,-5) ) ) +transpose(echo(transpose(transpose(X,-7) ,-7) ,4,6) ,7) ) ,-7) +echo(((arpeggio(((transpose(X,4) |echo(X,4,6) ) |X) ) |((X+X) |echo(X,4,6) ) ) +transpose(((shuffle(arpeggio((X+X) ) ) |transpose(((X+transpose(X,4) ) +transpose(X,7) ) ,-5) ) +transpose(arpeggio(transpose(((X+transpose(X,4) ) +transpose(X,7) ) ,-5) ) ,12) ) ,12) ) ,4,6) ) +transpose((arpeggio(step(step(X,12) ,12) ) +transpose(transpose(transpose(transpose(transpose(X,4) ,-5) ,-5) ,4) ,12) ) ,4) ) +transpose(transpose(((transpose(transpose(((X+transpose(X,4) ) +transpose(X,7) ) ,-5) ,4) +transpose(transpose(((X+transpose((X|X) ,4) ) +transpose((X+transpose(X,7) ) ,7) ) ,-7) ,12) ) |transpose(arpeggio(transpose(transpose((X+X) ,-7) ,-7) ) ,-5) ) ,4) ,7) ) ,12) ) ,4) ) +transpose(step(transpose(arpeggio(shuffle(((step(X,12) +transpose((arpeggio(X) |transpose(transpose(X,-7) ,4) ) ,4) ) +transpose(transpose((step(X,12) +X) ,4) ,7) ) ) ) ,-5) ,12) ,7) ) +transpose((((((((echo(echo(X,4,6) ,4,6) +((((X+transpose(X,4) ) +transpose(X,7) ) +(X|X) ) |transpose(X,4) ) ) +transpose(transpose(echo(echo(arpeggio(X) ,4,6) ,4,6) ,-5) ,7) ) +transpose(step(transpose(transpose((X+transpose(X,7) ) ,-7) ,-7) ,12) ,12) ) |((transpose(((X+transpose(X,7) ) +shuffle(X) ) ,4) +transpose(transpose((X|X) ,-7) ,12) ) |transpose((((transpose(step(X,12) ,-5) +transpose((X|X) ,4) ) +transpose((shuffle(X) |transpose(X,4) ) ,7) ) |(echo(X,4,6) +transpose((X+transpose(X,12) ) ,12) ) ) ,-5) ) ) +transpose(echo(((X|X) +transpose(X,12) ) ,4,6) ,12) ) |(step((((((shuffle(((arpeggio(X) +transpose((X|X) ,4) ) +transpose((X+X) ,7) ) ) +(X+transpose(X,7) ) ) |transpose((X+X) ,4) ) +transpose(echo((((X+transpose(X,12) ) +transpose(((X|X) +transpose((X+X) ,7) ) ,12) ) +(arpeggio(X) +transpose(X,4) ) ) ,4,6) ,4) ) +transpose((X+transpose((X+((X+transpose(X,7) ) +transpose(X,-7) ) ) ,12) ) ,7) ) +((transpose(((transpose(X,-5) +X) +transpose(transpose((X|X) ,4) ,-7) ) ,4) +transpose(X,4) ) +transpose(((step((X+transpose(X,12) ) ,12) +transpose(transpose(transpose(transpose(X,4) ,-5) ,4) ,12) ) +transpose((step(arpeggio(X) ,12) +(((X+X) +transpose(echo(X,4,6) ,4) ) +transpose((X|X) ,7) ) ) ,12) ) ,7) ) ) ,12) +step(transpose(transpose(((X+transpose(X,7) ) +(((X+transpose(X,4) ) +transpose(X,7) ) |X) ) ,-5) ,4) ,12) ) ) +(transpose(((step((X|(X+X) ) ,12) +transpose(transpose((((X+X) +transpose(X,-7) ) +transpose(((X|X) +X) ,7) ) ,4) ,4) ) +transpose(X,7) ) ,4) +transpose((shuffle(step(((X+X) +transpose((X+transpose(X,12) ) ,12) ) ,12) ) +(shuffle(transpose(echo(arpeggio(X) ,4,6) ,4) ) +transpose(echo(transpose(arpeggio(X) ,4) ,4,6) ,12) ) ) ,12) ) ) ,4) ) +transpose(transpose((step(step(transpose(transpose(X,4) ,-7) ,12) ,12) +transpose(transpose(transpose(arpeggio(transpose(transpose(transpose(X,-7) ,-7) ,4) ) ,-5) ,-7) ,12) ) ,-7) ,7) ) ,-5) +transpose((transpose(((transpose((((X+transpose(X,7) ) +transpose(transpose(X,4) ,7) ) +((transpose(transpose((X+transpose(X,12) ) ,-7) ,-7) +transpose(transpose(transpose(X,4) ,-5) ,4) ) +transpose(((X+transpose((transpose(X,-5) +transpose(X,12) ) ,4) ) +transpose(transpose(transpose(X,-7) ,-5) ,7) ) ,7) ) ) ,-7) +transpose((shuffle(X) +transpose((X+X) ,12) ) ,4) ) +transpose(arpeggio((((transpose(((X+transpose((X+X) ,4) ) +transpose(transpose(X,-5) ,7) ) ,4) |step(echo((((X+X) |(X+X) ) +transpose(arpeggio(X) ,12) ) ,4,6) ,12) ) +transpose(shuffle(((transpose(X,-7) +transpose(transpose(X,4) ,7) ) +(((transpose(X,4) +transpose(X,4) ) +transpose(X,7) ) |transpose(X,4) ) ) ) ,7) ) |(transpose((transpose((X+(X+X) ) ,4) +transpose((transpose(X,-7) +(X+transpose(X,7) ) ) ,7) ) ,-5) +transpose(transpose(((X+transpose(X,7) ) |((transpose(X,-7) |transpose(X,-5) ) |(transpose(X,-7) +X) ) ) ,4) ,7) ) ) ) ,7) ) ,4) +transpose(((transpose((((step(transpose(shuffle(arpeggio(X) ) ,-7) ,12) +transpose((((transpose(X,-5) +arpeggio(X) ) |(shuffle(X) +X) ) +transpose(transpose(step((X+X) ,12) ,4) ,7) ) ,-7) ) +transpose(transpose(transpose(transpose((transpose(step(transpose(X,4) ,12) ,-7) +transpose(transpose(transpose(X,4) ,4) ,7) ) ,-7) ,4) ,-7) ,4) ) +transpose(((echo(echo(X,4,6) ,4,6) +(X+arpeggio(X) ) ) |echo((((X+transpose((X|X) ,4) ) +transpose(X,7) ) +transpose((X|X) ,7) ) ,4,6) ) ,7) ) ,-7) +transpose(((transpose(transpose(shuffle(transpose(transpose(X,-5) ,4) ) ,4) ,-5) +transpose(echo(echo((step(echo(shuffle(X) ,4,6) ,12) +((arpeggio(transpose(transpose(X,-7) ,-5) ) +(X|X) ) +step(transpose(shuffle(X) ,-5) ,12) ) ) ,4,6) ,4,6) ,12) ) +transpose(((shuffle(((((X+X) +transpose((X+X) ,4) ) +transpose(X,7) ) |step(step(echo(X,4,6) ,12) ,12) ) ) +arpeggio(transpose(echo(transpose(transpose(X,-7) ,-7) ,4,6) ,4) ) ) |transpose(transpose((transpose((X+X) ,4) +(step(X,12) +transpose((X+transpose(X,12) ) ,7) ) ) ,4) ,-7) ) ,7) ) ,7) ) |arpeggio(transpose(transpose(((echo(((X|(X+transpose(X,7) ) ) |((X+X) |((X+transpose(X,4) ) +transpose(X,7) ) ) ) ,4,6) |((X+transpose(X,4) ) +transpose(X,7) ) ) +transpose((transpose(((transpose(X,-5) +transpose(X,4) ) +transpose(X,7) ) ,-7) +transpose(((echo(shuffle(X) ,4,6) +transpose(arpeggio(X) ,4) ) +transpose((X|X) ,7) ) ,12) ) ,12) ) ,-7) ,4) ) ) ,12) ) ,7) ) +transpose((transpose((transpose(((((step(transpose(arpeggio(transpose((arpeggio((X|X) ) +transpose(transpose((shuffle(X) +shuffle(X) ) ,-5) ,12) ) ,-5) ) ,4) ,12) +shuffle(((transpose(((transpose(X,-5) |transpose(X,-7) ) +(X|transpose(transpose(X,-7) ,-5) ) ) ,-7) +transpose(echo(echo(shuffle((X+transpose(X,12) ) ) ,4,6) ,4,6) ,7) ) +((transpose(transpose((X+X) ,-5) ,-7) |(shuffle(transpose((echo(X,4,6) +X) ,-7) ) +(transpose(X,-7) +echo(X,4,6) ) ) ) +transpose(((((X+transpose(((X+transpose(X,4) ) +transpose(X,7) ) ,4) ) +transpose(shuffle((X+transpose(X,7) ) ) ,7) ) +transpose(((X+X) +transpose(step((X+transpose((shuffle(X) +X) ,12) ) ,12) ,7) ) ,4) ) +transpose(transpose((transpose(echo(transpose(X,-5) ,4,6) ,-7) +X) ,-7) ,7) ) ,7) ) ) ) ) +transpose(transpose(((((transpose(transpose(((X|X) +transpose(transpose(X,-7) ,7) ) ,-7) ,-5) +transpose(transpose((transpose(transpose(X,-7) ,4) +transpose(X,4) ) ,-7) ,12) ) +step((X|X) ,12) ) +transpose(shuffle(((transpose((transpose(X,-7) +transpose(transpose(X,-7) ,7) ) ,-5) +transpose(arpeggio(transpose(transpose(X,4) ,-7) ) ,4) ) +transpose(transpose(transpose(arpeggio((X+X) ) ,-5) ,-7) ,7) ) ) ,7) ) |arpeggio(echo((((echo(X,4,6) +transpose(X,-7) ) +(arpeggio(transpose(X,-7) ) |(X|transpose(X,-5) ) ) ) |((X|step(X,12) ) |echo((X+X) ,4,6) ) ) ,4,6) ) ) ,-7) ,4) ) +transpose(transpose((arpeggio(transpose(transpose(echo(shuffle(X) ,4,6) ,-5) ,4) ) |(((shuffle(transpose(step(arpeggio(X) ,12) ,-7) ) +transpose((transpose(((X+X) +transpose((arpeggio(X) +arpeggio(transpose(X,4) ) ) ,7) ) ,4) +transpose((transpose(transpose(X,4) ,4) |((X+transpose(X,12) ) +transpose(X,12) ) ) ,-5) ) ,4) ) +transpose(transpose(echo(transpose((X+X) ,-7) ,4,6) ,4) ,7) ) |((transpose((X|(X+X) ) ,-7) +(transpose((X|(X|X) ) ,-5) +(echo((X|X) ,4,6) +transpose((X+transpose(X,12) ) ,-5) ) ) ) +transpose((step(X,12) +transpose(((transpose(X,4) +transpose(transpose(X,4) ,7) ) +transpose(((X+transpose(X,12) ) +(X|X) ) ,12) ) ,7) ) ,-7) ) ) ) ,-5) ,7) ) +transpose(transpose(step((transpose((shuffle(X) +transpose(transpose(X,4) ,7) ) ,-5) |(arpeggio(transpose(step(X,12) ,-5) ) +X) ) ,12) ,-5) ,7) ) ,4) +echo(shuffle(transpose(((shuffle(shuffle(echo((transpose((transpose(X,-7) +transpose(X,12) ) ,4) +transpose(echo(X,4,6) ,7) ) ,4,6) ) ) +((arpeggio((((X+transpose(X,7) ) +transpose(transpose(((arpeggio(((X+transpose(X,12) ) +transpose(transpose(X,-5) ,12) ) ) +transpose(((X+transpose(X,7) ) |((X+transpose(X,4) ) +transpose(X,7) ) ) ,4) ) +transpose(arpeggio(echo(transpose(X,4) ,4,6) ) ,7) ) ,4) ,4) ) +transpose(((X+transpose(transpose(step(X,12) ,4) ,4) ) +transpose(arpeggio(X) ,7) ) ,7) ) ) +transpose(shuffle(transpose((step(transpose((X+transpose(X,-5) ) ,-5) ,12) +transpose(echo((((X+X) +transpose(X,4) ) +transpose(X,7) ) ,4,6) ,12) ) ,4) ) ,4) ) +transpose(echo((((((X+transpose(X,7) ) +transpose(transpose(((X+transpose(X,4) ) +transpose(X,7) ) ,4) ,4) ) +transpose((X|X) ,7) ) +(arpeggio(transpose(X,-5) ) +transpose(step(X,12) ,7) ) ) +transpose(transpose(echo(transpose((X|X) ,-5) ,4,6) ,-5) ,7) ) ,4,6) ,7) ) ) |(((arpeggio(transpose(transpose(transpose(arpeggio(X) ,-7) ,-5) ,4) ) +transpose(transpose(((echo((transpose(transpose((transpose(X,-7) +transpose(X,-7) ) ,4) ,-7) +((X+transpose(X,7) ) |((X+transpose(X,4) ) +transpose(X,7) ) ) ) ,4,6) +transpose(transpose(((transpose(echo(X,4,6) ,-5) +transpose(transpose((X+transpose(X,7) ) ,4) ,7) ) +transpose(shuffle(((X+transpose(X,4) ) +transpose(X,7) ) ) ,12) ) ,4) ,4) ) +transpose(shuffle(transpose(X,4) ) ,7) ) ,-7) ,4) ) +transpose(arpeggio((transpose(((step(echo(transpose(X,-7) ,4,6) ,12) +transpose(transpose((X|X) ,4) ,4) ) +transpose(((X+X) +transpose((X+transpose(X,7) ) ,-7) ) ,7) ) ,-7) |transpose((((X|X) +transpose((X+transpose(X,7) ) ,12) ) +transpose((step(transpose(X,-7) ,12) +transpose((echo(X,4,6) +step(X,12) ) ,7) ) ,12) ) ,4) ) ) ,7) ) |arpeggio(transpose(transpose(((arpeggio(X) +transpose((X|X) ,12) ) +((X+X) +transpose(transpose(transpose(X,-7) ,-5) ,12) ) ) ,-5) ,-5) ) ) ) ,4) ) ,4,6) ) ,-7) |(echo(transpose(shuffle(((arpeggio(transpose(((X+transpose(X,-7) ) |(X+X) ) ,-7) ) +((transpose(step(transpose((X+transpose(X,12) ) ,-7) ,12) ,-5) +transpose(echo(transpose(X,4) ,4,6) ,12) ) +(transpose(transpose((transpose(X,-7) +transpose((X|X) ,7) ) ,4) ,-7) +(transpose((X+transpose(X,12) ) ,4) +transpose(echo(X,4,6) ,4) ) ) ) ) +transpose((transpose((((((X+transpose(X,4) ) +transpose(X,7) ) +transpose(step((X|X) ,12) ,12) ) +transpose(echo((arpeggio(X) +transpose(arpeggio(X) ,7) ) ,4,6) ,4) ) +transpose((X+transpose(arpeggio(shuffle(X) ) ,12) ) ,7) ) ,-5) +(step(transpose(echo(echo(X,4,6) ,4,6) ,-7) ,12) +transpose((step((transpose((X+X) ,-7) +transpose(transpose(X,-7) ,7) ) ,12) +transpose(((X+transpose(X,7) ) |(((transpose(X,-7) +transpose(X,4) ) +transpose(X,7) ) +transpose(arpeggio((X|X) ) ,12) ) ) ,12) ) ,12) ) ) ,12) ) ) ,4) ,4,6) +transpose(transpose(arpeggio(((step(step((shuffle(((X+transpose(X,12) ) +(X|X) ) ) +transpose((transpose(X,4) +(((X+transpose(X,4) ) +transpose(X,7) ) +transpose(transpose(X,4) ,12) ) ) ,12) ) ,12) ,12) +transpose((((((X+transpose(X,12) ) +transpose(((X+X) +transpose(X,4) ) ,4) ) +transpose((((X+transpose(X,4) ) +transpose(X,7) ) +((X+X) |X) ) ,7) ) +transpose(((((((X|X) +arpeggio(X) ) +(X+X) ) +transpose(arpeggio(((X+transpose(transpose(X,-5) ,4) ) +transpose(transpose(X,4) ,7) ) ) ,12) ) +transpose(((X+transpose(X,4) ) +transpose(X,7) ) ,-7) ) +transpose((echo((X|X) ,4,6) +transpose(transpose(X,-5) ,7) ) ,4) ) ,4) ) +transpose((transpose((X|(shuffle(X) +((X+transpose(X,4) ) +transpose(X,7) ) ) ) ,-5) +transpose((X+transpose((echo(X,4,6) +X) ,-5) ) ,12) ) ,7) ) ,4) ) +transpose(transpose(shuffle(transpose((echo(transpose((X+transpose(X,7) ) ,-7) ,4,6) +transpose(transpose(transpose((X+transpose(X,12) ) ,4) ,-5) ,7) ) ,4) ) ,-7) ,7) ) ) ,-7) ,7) ) ) ,12) ) |((((transpose(transpose(transpose(transpose(X,-7) ,-7) ,4) ,-5) |(step((((((((shuffle(arpeggio(X) ) +transpose(((X+transpose(X,4) ) +transpose(((X+transpose(X,4) ) +transpose(X,7) ) ,7) ) ,4) ) +transpose(transpose((X+X) ,-7) ,7) ) +transpose(X,-7) ) +transpose(((echo(X,4,6) +X) +transpose(transpose(arpeggio(X) ,4) ,12) ) ,4) ) +transpose((transpose((((((X+transpose(X,4) ) +transpose(X,7) ) +transpose(transpose(X,4) ,4) ) +transpose(X,7) ) |transpose(transpose(X,-7) ,-5) ) ,-5) +arpeggio(X) ) ,7) ) +transpose((((((X+X) +transpose(((X|X) +transpose(step(X,12) ,7) ) ,12) ) +transpose(transpose(transpose(transpose(X,4) ,-7) ,-5) ,12) ) |transpose(transpose(X,-7) ,-7) ) |(((transpose(((echo(X,4,6) +transpose(X,4) ) +transpose(X,7) ) ,-7) +transpose(transpose(transpose(X,-7) ,4) ,12) ) +transpose(echo((echo(X,4,6) +X) ,4,6) ,4) ) +transpose(shuffle(shuffle(transpose(X,4) ) ) ,7) ) ) ,7) ) +transpose(arpeggio((arpeggio(transpose(transpose(X,-5) ,4) ) +transpose(transpose(X,-7) ,12) ) ) ,12) ) ,12) +transpose((shuffle((echo(X,4,6) +transpose(transpose(arpeggio(step((shuffle(((X+transpose(X,4) ) +transpose(X,7) ) ) +(X|X) ) ,12) ) ,4) ,12) ) ) +(transpose((transpose(X,-5) +transpose(X,12) ) ,-7) +(transpose(X,-5) |((X+transpose(X,12) ) +X) ) ) ) ,7) ) ) +transpose(((step((echo((X+transpose(X,7) ) ,4,6) +((X+transpose(X,-7) ) +transpose((transpose(((X+transpose(X,-7) ) |step(X,12) ) ,4) +transpose(echo(shuffle((transpose(X,-7) +transpose(X,7) ) ) ,4,6) ,12) ) ,12) ) ) ,12) +transpose((transpose(((transpose(((X+transpose(X,12) ) +(step((X+X) ,12) +transpose(step(X,12) ,7) ) ) ,-7) +transpose(((((transpose(X,-7) +transpose((X+transpose(X,7) ) ,12) ) +echo(((X+X) +transpose((X+X) ,7) ) ,4,6) ) +(X|step(shuffle(X) ,12) ) ) +((transpose(transpose(X,-5) ,-5) +echo((X|step(X,12) ) ,4,6) ) +transpose((transpose(transpose(echo(X,4,6) ,-7) ,-7) +shuffle(arpeggio(transpose(X,-7) ) ) ) ,12) ) ) ,12) ) |step(((transpose(echo(shuffle(shuffle(X) ) ,4,6) ,4) +transpose(echo((transpose(arpeggio(X) ,-7) +transpose(transpose(X,4) ,12) ) ,4,6) ,12) ) +transpose((transpose(((X+X) +echo(X,4,6) ) ,-5) |(transpose(((X|X) |transpose(X,-7) ) ,-7) +(((X|X) +transpose(transpose(X,-5) ,4) ) +transpose(((X+transpose(X,12) ) +transpose(echo(X,4,6) ,7) ) ,7) ) ) ) ,12) ) ,12) ) ,-5) +((arpeggio((step(step(X,12) ,12) +transpose(((((((X+transpose(X,4) ) +transpose(X,7) ) +transpose(X,4) ) +transpose(transpose(X,-5) ,7) ) +transpose((X|(X|X) ) ,7) ) |(((X+transpose(X,7) ) +transpose(((X+transpose(X,4) ) +transpose(X,7) ) ,4) ) +transpose(transpose(X,-5) ,7) ) ) ,12) ) ) +transpose((arpeggio((step(((X+transpose(X,4) ) +transpose(X,7) ) ,12) +transpose(transpose((X+transpose(X,7) ) ,4) ,4) ) ) +transpose(transpose(step(transpose(((X+transpose(echo(X,4,6) ,12) ) +(transpose(X,4) +X) ) ,-7) ,12) ,4) ,7) ) ,7) ) |transpose(step((echo((X+X) ,4,6) +(transpose((X|X) ,-7) +(transpose((X+X) ,-5) +transpose(X,12) ) ) ) ,12) ,-7) ) ) ,4) ) +transpose(transpose((step(((((X|(X|X) ) +transpose(shuffle(X) ,12) ) +echo(X,4,6) ) |(transpose(transpose((X+X) ,-7) ,4) +arpeggio(X) ) ) ,12) +transpose(((step(echo(arpeggio((X+transpose(X,12) ) ) ,4,6) ,12) +transpose((transpose((X+X) ,4) +transpose(transpose(X,4) ,12) ) ,4) ) +transpose(transpose(((X+transpose(X,7) ) +transpose((((X|X) +transpose(transpose(X,-5) ,7) ) +transpose(transpose(arpeggio(X) ,-5) ,12) ) ,12) ) ,-7) ,7) ) ,12) ) ,-5) ,7) ) ,12) ) +transpose((((transpose(X,-5) |X) |(transpose(transpose(((X+X) +transpose(transpose(X,-5) ,12) ) ,-7) ,-5) +transpose(transpose(transpose(echo(step(X,12) ,4,6) ,-5) ,4) ,7) ) ) +((((((arpeggio((X+X) ) |transpose((X|X) ,-5) ) |transpose(X,-7) ) +transpose(((step(((X+transpose(X,4) ) +transpose(X,7) ) ,12) +X) |echo(shuffle((X|X) ) ,4,6) ) ,4) ) +transpose(transpose(step(((X+transpose(shuffle(X) ,4) ) +transpose((X+X) ,7) ) ,12) ,4) ,7) ) |echo(shuffle(transpose(X,4) ) ,4,6) ) +arpeggio((transpose((echo(echo(arpeggio(X) ,4,6) ,4,6) |((echo(X,4,6) +transpose((X+transpose(X,12) ) ,12) ) |transpose(transpose(X,4) ,-7) ) ) ,-5) +transpose((echo(transpose((transpose(X,-5) +(X+X) ) ,4) ,4,6) +transpose(transpose(transpose(echo(X,4,6) ,4) ,4) ,4) ) ,12) ) ) ) ) ,7) ) |(arpeggio((transpose(shuffle(arpeggio(((X+transpose(X,4) ) +transpose(X,7) ) ) ) ,-7) |((transpose(transpose(X,-5) ,4) |(transpose(shuffle((X|X) ) ,4) |echo(step(X,12) ,4,6) ) ) +transpose(transpose(X,4) ,-7) ) ) ) |(transpose(step(((transpose(((step((echo((X+X) ,4,6) +transpose(arpeggio((X|X) ) ,12) ) ,12) +transpose(shuffle((transpose(transpose(X,-5) ,-7) +transpose(transpose(X,-7) ,4) ) ) ,4) ) +transpose(transpose(X,-5) ,7) ) ,-7) +(arpeggio(transpose(echo(X,4,6) ,4) ) +(step(transpose(X,-5) ,12) +((X+transpose(X,7) ) +transpose(transpose(X,4) ,12) ) ) ) ) +transpose((((X+transpose(X,7) ) +transpose((X|X) ,4) ) |transpose(((X+X) +transpose(step(transpose(X,4) ,12) ,12) ) ,-7) ) ,-7) ) ,12) ,4) +transpose(transpose(transpose((((transpose(transpose((X+transpose(X,7) ) ,-5) ,-5) +transpose(transpose(transpose(echo(X,4,6) ,-7) ,-5) ,7) ) +transpose(transpose(((transpose(X,4) +transpose(transpose(X,-5) ,12) ) +echo(((X+transpose(X,4) ) +transpose(X,7) ) ,4,6) ) ,4) ,4) ) +transpose(transpose((X+transpose(X,7) ) ,-5) ,7) ) ,-5) ,-7) ,12) ) ) ) )
random seed used was 173198449

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