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(transpose(transpose((transpose(transpose(((echo(X,4,6) +transpose((X+X) ,4) ) +transpose(X,7) ) ,-7) ,-5) +transpose(echo(transpose(transpose((echo(X,4,6) |X) ,4) ,4) ,4,6) ,12) ) ,-5) ,4) ) +transpose(arpeggio((arpeggio(transpose(transpose(transpose((((X+transpose(X,12) ) +transpose(transpose(transpose((X|X) ,-5) ,-5) ,7) ) +transpose((transpose(X,-5) |(X+X) ) ,-7) ) ,4) ,-7) ,4) ) |shuffle(((((echo((((((transpose(X,4) +transpose(X,4) ) +transpose(step(X,12) ,7) ) +transpose(shuffle((X+transpose(X,12) ) ) ,4) ) +transpose((X+X) ,7) ) |(shuffle(transpose(X,-5) ) |echo(X,4,6) ) ) ,4,6) |echo((((X+transpose(X,7) ) +transpose(X,12) ) |X) ,4,6) ) +transpose(transpose(((echo(arpeggio(X) ,4,6) +transpose(X,12) ) +transpose(shuffle(arpeggio(X) ) ,12) ) ,4) ,12) ) +transpose(transpose(transpose(((((X+transpose(X,4) ) +transpose(X,7) ) +transpose((X+X) ,12) ) +transpose(step(X,12) ,12) ) ,-7) ,-7) ,4) ) +transpose(arpeggio((step(X,12) +transpose(((transpose(X,4) +transpose(X,12) ) +arpeggio(X) ) ,7) ) ) ,7) ) ) ) ) ,12) ) +transpose((((arpeggio((arpeggio(step((((transpose(X,4) +transpose(X,4) ) +transpose(transpose(((X+transpose(X,4) ) +transpose(X,7) ) ,4) ,7) ) +((step(transpose(X,4) ,12) +transpose((X|X) ,4) ) +transpose(transpose((X+transpose(X,12) ) ,-5) ,7) ) ) ,12) ) +transpose(transpose(transpose((X+X) ,-7) ,4) ,12) ) ) +(echo((transpose((transpose((X+transpose(X,7) ) ,-5) +transpose((transpose(X,4) +((X+transpose(X,12) ) +transpose((X+transpose(X,7) ) ,12) ) ) ,7) ) ,4) |transpose(echo((arpeggio(X) +((X|X) +transpose(transpose(X,-5) ,12) ) ) ,4,6) ,-7) ) ,4,6) |(shuffle(arpeggio(transpose(X,4) ) ) +(transpose(((shuffle(transpose((X|X) ,-7) ) +transpose((transpose(X,4) |((X+transpose(X,12) ) +transpose((X|X) ,12) ) ) ,12) ) |((X|X) +transpose((X+transpose(X,12) ) ,7) ) ) ,-5) |transpose(transpose((((X+transpose(X,4) ) +transpose(X,7) ) |(X+transpose(X,12) ) ) ,-5) ,-7) ) ) ) ) +((transpose(transpose(step((X+X) ,12) ,-7) ,-5) +arpeggio(transpose(arpeggio(transpose(arpeggio(((X|X) +transpose(X,7) ) ) ,-7) ) ,-5) ) ) +transpose(step((transpose((echo(X,4,6) +transpose(((transpose(X,-7) +transpose((X+transpose(X,12) ) ,7) ) +transpose((X+(X+X) ) ,12) ) ,12) ) ,4) +transpose(((((echo((X+transpose(X,7) ) ,4,6) +transpose(echo(X,4,6) ,7) ) +(transpose(arpeggio(X) ,-5) +transpose(((X+transpose(X,12) ) |X) ,12) ) ) +(transpose((X+transpose(X,12) ) ,4) |transpose(X,-7) ) ) +shuffle((step(transpose(X,-5) ,12) +(X|(X+X) ) ) ) ) ,-7) ) ,12) ,7) ) ) |(transpose(((((transpose(X,4) |((transpose(transpose((X+X) ,-5) ,-5) +transpose(transpose((transpose(X,4) +step(X,12) ) ,4) ,4) ) +transpose(echo((X|X) ,4,6) ,7) ) ) +((arpeggio(X) +transpose(arpeggio(((X+transpose(X,4) ) +transpose(X,7) ) ) ,12) ) +echo(X,4,6) ) ) +(transpose(transpose(transpose(X,-5) ,-5) ,-7) +transpose((((X+transpose(X,7) ) +transpose(transpose(transpose(echo(arpeggio(X) ,4,6) ,-7) ,-5) ,4) ) +transpose((arpeggio((X+X) ) +echo(X,4,6) ) ,7) ) ,12) ) ) +((step(((transpose(X,-5) +transpose(arpeggio(echo(X,4,6) ) ,4) ) +transpose((shuffle(X) +(transpose(X,4) +(X+X) ) ) ,7) ) ,12) +transpose(transpose(arpeggio(step(X,12) ) ,4) ,7) ) +transpose((shuffle((arpeggio(transpose(X,-5) ) +transpose(shuffle(X) ,7) ) ) +((transpose((X+transpose((X+X) ,7) ) ,-7) +transpose(transpose(((X+X) |shuffle(X) ) ,-7) ,4) ) +transpose(transpose(X,-7) ,7) ) ) ,12) ) ) ,-7) +transpose(transpose((transpose(((transpose(step((transpose((X+transpose(X,7) ) ,4) |(transpose(echo(echo(X,4,6) ,4,6) ,4) +transpose(transpose(X,4) ,12) ) ) ,12) ,-5) +transpose(((((transpose(X,-5) +((shuffle((arpeggio(X) +transpose(X,7) ) ) +transpose((X|transpose((X+transpose(X,12) ) ,4) ) ,4) ) +transpose(transpose((X|X) ,-7) ,7) ) ) |shuffle(transpose(step((X+transpose(X,12) ) ,12) ,4) ) ) +transpose(((transpose(transpose(step(X,12) ,4) ,-7) |X) +(arpeggio(echo(X,4,6) ) +transpose(arpeggio(((X+transpose(shuffle(X) ,4) ) +transpose(echo(X,4,6) ,7) ) ) ,12) ) ) ,4) ) +transpose(((transpose(transpose(X,4) ,-5) |((transpose(transpose(X,-5) ,-5) +transpose(arpeggio((X+step(X,12) ) ) ,4) ) +transpose(((X+transpose(X,12) ) +echo(transpose(X,-7) ,4,6) ) ,7) ) ) +transpose(transpose(echo(transpose(transpose(X,-5) ,-5) ,4,6) ,-5) ,12) ) ,7) ) ,4) ) +transpose(((transpose((transpose(((X+transpose(X,12) ) +(X|X) ) ,-5) |echo((X+X) ,4,6) ) ,-7) +transpose((transpose(transpose(X,4) ,4) +transpose((((X+transpose(X,12) ) +transpose(arpeggio(X) ,4) ) +transpose(transpose(X,-5) ,7) ) ,12) ) ,12) ) +((transpose(((X+transpose(arpeggio(X) ,7) ) +transpose(((X+transpose(X,4) ) +transpose(X,7) ) ,4) ) ,4) |X) +transpose(shuffle(X) ,-5) ) ) ,7) ) ,-7) |echo((transpose(shuffle(transpose(transpose(X,-5) ,-7) ) ,-5) +transpose(transpose((echo(arpeggio(X) ,4,6) |(transpose(X,4) |transpose((X|X) ,-7) ) ) ,4) ,12) ) ,4,6) ) ,4) ,7) ) ) ,12) ) |echo((transpose(arpeggio(shuffle((echo(((((((transpose(X,4) +transpose(X,4) ) +transpose(transpose((X+transpose(X,7) ) ,-5) ,7) ) |step(X,12) ) +transpose(((X+(X|X) ) +transpose(((X|X) |transpose(X,-5) ) ,12) ) ,12) ) +transpose((((X+transpose(X,7) ) |X) +transpose(shuffle(step(transpose(X,4) ,12) ) ,12) ) ,12) ) +shuffle(transpose(step(X,12) ,-7) ) ) ,4,6) +transpose(transpose((((((X+transpose(X,4) ) +transpose(X,7) ) +transpose(arpeggio(transpose(X,4) ) ,4) ) +transpose(X,7) ) +transpose((X|step((X+X) ,12) ) ,7) ) ,-5) ,7) ) ) ) ,-7) +transpose(echo(transpose(arpeggio(((echo((transpose(transpose(X,4) ,-7) +shuffle(transpose(((X+transpose(X,7) ) +transpose(X,-5) ) ,-5) ) ) ,4,6) +transpose(transpose((step(transpose(X,4) ,12) +(arpeggio(X) |(shuffle(X) |((transpose(X,4) |(X|X) ) |transpose(X,-7) ) ) ) ) ,-7) ,4) ) +transpose((transpose(transpose(((((((X+transpose(X,4) ) +transpose(X,7) ) +transpose(X,12) ) +transpose((X+transpose(((X|X) |X) ,12) ) ,12) ) +transpose(transpose(echo(transpose(X,4) ,4,6) ,-7) ,4) ) +transpose((transpose((X|X) ,4) |(X+transpose((X|X) ,7) ) ) ,7) ) ,-7) ,-7) +transpose(shuffle(((transpose((((X+X) +transpose(X,4) ) +transpose(transpose(transpose(X,4) ,4) ,7) ) ,-5) +transpose(transpose(transpose(transpose(X,4) ,-7) ,4) ,4) ) +transpose(((transpose(((step(X,12) +transpose(transpose(X,4) ,4) ) +transpose((X+transpose(X,7) ) ,7) ) ,-7) +transpose(((X|X) |X) ,4) ) +transpose(arpeggio((((X|X) +transpose(X,4) ) +transpose(echo(X,4,6) ,7) ) ) ,7) ) ,7) ) ) ,7) ) ,7) ) ) ,-5) ,4,6) ,12) ) ,4,6) ) +transpose(step((step(transpose(shuffle((((transpose(transpose((step(transpose(X,4) ,12) +transpose((transpose(X,4) +transpose((arpeggio(X) +transpose(X,12) ) ,7) ) ,12) ) ,-5) ,4) +transpose(echo(((((transpose(transpose(echo(X,4,6) ,4) ,4) +transpose((transpose(X,4) |transpose((X+X) ,-7) ) ,7) ) +((step(X,12) +transpose(transpose(X,-7) ,4) ) +transpose(echo(X,4,6) ,7) ) ) +transpose(((transpose((X|X) ,4) +transpose((X+transpose(((X+transpose(X,4) ) +transpose(X,7) ) ,12) ) ,4) ) +transpose(((((echo(X,4,6) +transpose(X,4) ) +transpose(transpose(X,4) ,7) ) +transpose(arpeggio((X|X) ) ,12) ) |((X+transpose(X,-7) ) +(X+transpose(X,12) ) ) ) ,7) ) ,4) ) +transpose(arpeggio(transpose(transpose(X,-7) ,-5) ) ,7) ) ,4,6) ,4) ) +transpose(arpeggio((((((X+transpose((echo(X,4,6) |(X+X) ) ,4) ) +transpose((echo(X,4,6) +(X+X) ) ,7) ) +(echo(((((X+transpose(X,4) ) +transpose(X,7) ) +transpose((X+transpose(X,7) ) ,4) ) +transpose(transpose(X,4) ,7) ) ,4,6) +transpose((transpose(X,-7) +transpose((X+transpose(X,-5) ) ,7) ) ,7) ) ) +transpose(step(transpose(transpose(shuffle((X+transpose(X,7) ) ) ,-7) ,-5) ,12) ,4) ) +transpose(transpose((((X+transpose(X,4) ) +transpose(X,7) ) +step(arpeggio(X) ,12) ) ,-7) ,7) ) ) ,7) ) +((transpose((X+transpose(X,12) ) ,4) +transpose(X,-7) ) |transpose((transpose(transpose(transpose(X,-7) ,-5) ,4) +transpose(echo(((X+transpose(X,4) ) +transpose(X,7) ) ,4,6) ,4) ) ,4) ) ) ) ,-7) ,12) |(transpose(transpose((shuffle(transpose(transpose(((transpose(transpose(((X+transpose(X,4) ) +transpose(X,7) ) ,4) ,-5) |echo(X,4,6) ) |arpeggio((transpose(echo(X,4,6) ,4) +transpose(X,-7) ) ) ) ,-5) ,-5) ) +transpose((((transpose(transpose((step(X,12) +transpose(echo(X,4,6) ,12) ) ,4) ,-7) +transpose((((((X+transpose(X,4) ) +transpose(X,7) ) +X) |transpose((X|X) ,-7) ) +transpose(step(step((((X+X) +transpose(((X+transpose(X,4) ) +transpose(X,7) ) ,4) ) +transpose(X,7) ) ,12) ,12) ,12) ) ,12) ) +((((shuffle(transpose((X+X) ,4) ) |transpose(shuffle((X+X) ) ,4) ) |arpeggio(X) ) |transpose((step(echo(X,4,6) ,12) +transpose(((X|X) +transpose(shuffle(X) ,12) ) ,12) ) ,-7) ) +transpose((((transpose(((X|X) +transpose((((X|X) +transpose((X+X) ,4) ) +transpose((X|X) ,7) ) ,12) ) ,-7) +(transpose(X,4) +transpose(transpose(shuffle(X) ,-7) ,7) ) ) +transpose(transpose(((X+transpose(X,4) ) +transpose(X,7) ) ,-7) ,12) ) +transpose(transpose(transpose(arpeggio(X) ,-5) ,-5) ,7) ) ,7) ) ) +((echo((((transpose(((X+X) |(X+transpose(X,7) ) ) ,4) +transpose(transpose(((X+transpose(X,12) ) +X) ,4) ,4) ) +transpose((transpose(((X+transpose(X,7) ) |echo(X,4,6) ) ,-5) |(X|transpose(X,4) ) ) ,7) ) |echo(((transpose(X,4) +transpose(((X+transpose(X,7) ) |step(X,12) ) ,7) ) |((transpose((X|X) ,4) +transpose(transpose(X,4) ,7) ) |(transpose(X,-7) +(X|echo(X,4,6) ) ) ) ) ,4,6) ) ,4,6) +transpose((echo((arpeggio(transpose((X+X) ,4) ) +transpose(transpose((((X|arpeggio(X) ) +transpose(X,12) ) +((arpeggio(X) +transpose(((X+transpose(X,12) ) +X) ,4) ) +transpose(X,7) ) ) ,-7) ,12) ) ,4,6) +((transpose(transpose(X,-5) ,-5) +transpose(step(shuffle(X) ,12) ,7) ) +transpose(echo(transpose(X,4) ,4,6) ,12) ) ) ,4) ) +transpose((((transpose(((X+transpose((X+X) ,4) ) +transpose((X+transpose(X,7) ) ,7) ) ,-7) |((((X+transpose(X,7) ) +X) |transpose(X,-7) ) +echo(arpeggio(X) ,4,6) ) ) +transpose(transpose((transpose(step(((transpose(X,-7) +transpose((X+transpose(X,7) ) ,4) ) +transpose(X,7) ) ,12) ,-5) +transpose((transpose(transpose(arpeggio(X) ,4) ,4) +transpose((X+X) ,7) ) ,12) ) ,-5) ,4) ) +transpose(echo(arpeggio(((X+transpose(X,4) ) +transpose(X,7) ) ) ,4,6) ,7) ) ,7) ) ) ,12) ) ,-7) ,4) +transpose(step((transpose((transpose(X,-5) +transpose(((((echo(((X+transpose(transpose(X,4) ,4) ) +transpose((X|X) ,7) ) ,4,6) +transpose(((X|transpose(X,-5) ) +transpose(((((X+transpose(X,4) ) +transpose(X,7) ) +X) +transpose(echo(X,4,6) ,12) ) ,7) ) ,7) ) +echo(transpose(transpose(transpose(X,4) ,-5) ,-5) ,4,6) ) +(((X+X) +transpose(X,12) ) +transpose(transpose((transpose(X,4) +transpose(X,-5) ) ,-7) ,7) ) ) +step(arpeggio((shuffle(X) |(arpeggio(transpose(X,-5) ) +shuffle((X+transpose(X,12) ) ) ) ) ) ,12) ) ,12) ) ,-5) |shuffle(transpose(((transpose(transpose(transpose(transpose(X,4) ,-7) ,-7) ,-5) +transpose(step(transpose(transpose(step(echo(X,4,6) ,12) ,-5) ,4) ,12) ,7) ) |transpose((arpeggio((X|(X+transpose(X,12) ) ) ) +(((echo((X|X) ,4,6) |arpeggio(X) ) +transpose(shuffle(X) ,4) ) +transpose((X|X) ,7) ) ) ,4) ) ,-5) ) ) ,12) ,12) ) ) ,12) ,4) ) +transpose(((transpose(((shuffle(transpose(((transpose(arpeggio((arpeggio(X) +transpose(((transpose(X,-5) +transpose(((X+transpose(X,4) ) +transpose(X,7) ) ,4) ) +transpose((X+transpose(X,12) ) ,7) ) ,12) ) ) ,-5) +shuffle(transpose(arpeggio(X) ,4) ) ) +(((echo((arpeggio((transpose(X,4) +X) ) +echo((((transpose(X,-7) +transpose(X,4) ) +transpose((X+transpose(X,7) ) ,7) ) +(arpeggio(X) +shuffle(X) ) ) ,4,6) ) ,4,6) +transpose(step(shuffle(transpose(transpose(X,-5) ,-7) ) ,12) ,7) ) |shuffle(((X+transpose(X,7) ) |shuffle(X) ) ) ) +transpose(echo(echo(((transpose(((step(X,12) |X) +transpose((transpose(X,-7) +X) ,12) ) ,-5) +transpose(transpose(transpose(echo(transpose(shuffle(X) ,4) ,4,6) ,-7) ,4) ,4) ) +transpose(((((X+X) +transpose(transpose(X,4) ,7) ) |((X|transpose(X,-7) ) |(X+transpose((X+transpose(X,7) ) ,7) ) ) ) +transpose((transpose((echo(X,4,6) +transpose(X,7) ) ,4) +transpose((((X|((X+transpose(X,4) ) +transpose(X,7) ) ) +transpose((X+transpose(echo(X,4,6) ,12) ) ,4) ) +transpose((transpose(X,-7) +transpose(X,12) ) ,7) ) ,12) ) ,12) ) ,7) ) ,4,6) ,4,6) ,4) ) ) ,-5) ) +transpose(transpose(step(transpose(step(((echo(arpeggio(((((X+transpose(X,7) ) +transpose(((X+transpose(X,12) ) +X) ,4) ) +transpose(transpose(transpose(X,-7) ,4) ,7) ) +transpose(X,7) ) ) ,4,6) +transpose(step((transpose((transpose(X,-5) +transpose((X+transpose(transpose(X,-5) ,12) ) ,12) ) ,-5) |((arpeggio(echo(X,4,6) ) |(transpose(X,-5) +((X+transpose(X,4) ) +transpose(X,7) ) ) ) +transpose(X,4) ) ) ,12) ,4) ) +transpose(step(arpeggio(((X|X) |(X+transpose(X,7) ) ) ) ,12) ,7) ) ,12) ,4) ,12) ,-7) ,4) ) +transpose(((((transpose(step(transpose(transpose(transpose(transpose(X,4) ,4) ,-5) ,-7) ,12) ,-5) +transpose((echo(echo(transpose(transpose((X+transpose(((X+transpose(X,4) ) +transpose(X,7) ) ,7) ) ,-7) ,-5) ,4,6) ,4,6) +transpose(transpose(transpose(((transpose(transpose(X,-7) ,4) |shuffle((X+transpose(X,7) ) ) ) +((((transpose(X,-5) +transpose((X+transpose(X,7) ) ,4) ) +transpose(echo(X,4,6) ,7) ) +transpose(((X+transpose(X,4) ) +transpose(X,7) ) ,4) ) +transpose(((X+transpose(X,12) ) +transpose(X,12) ) ,7) ) ) ,-7) ,4) ,-5) ) ,7) ) +transpose(transpose((arpeggio(transpose((shuffle(transpose((X|X) ,4) ) +(shuffle((X+transpose(X,7) ) ) +transpose(((X+X) |shuffle(X) ) ,7) ) ) ,-7) ) +(transpose(((X|X) +transpose(transpose((X+transpose(X,7) ) ,-7) ,12) ) ,4) |echo((((X+arpeggio(X) ) +transpose(transpose((X+X) ,4) ,12) ) +transpose(shuffle(X) ,-5) ) ,4,6) ) ) ,-7) ,4) ) +transpose((transpose(((((arpeggio(X) +((X+transpose(X,12) ) +X) ) +((transpose((X+X) ,4) +transpose(((X+transpose(X,7) ) |(X+transpose(X,12) ) ) ,4) ) +transpose(transpose(echo(X,4,6) ,-5) ,7) ) ) +step(X,12) ) |(transpose((transpose(X,4) |X) ,-7) +(((X+transpose(X,4) ) +transpose(X,7) ) +((X+transpose(X,12) ) |((transpose(X,4) +transpose(X,4) ) +transpose(X,7) ) ) ) ) ) ,4) +transpose(transpose((((((((X+transpose(X,4) ) +transpose(X,7) ) |(X+transpose(X,7) ) ) +transpose(transpose(transpose((X|X) ,-7) ,-5) ,7) ) +transpose(transpose(transpose(step(X,12) ,-5) ,4) ,4) ) +transpose(transpose(step(transpose((X|X) ,-7) ,12) ,-5) ,7) ) |transpose(transpose(transpose((((X|X) +transpose(X,4) ) +transpose(transpose(X,4) ,7) ) ,-5) ,-5) ,4) ) ,-5) ,12) ) ,7) ) +transpose(transpose(arpeggio((((step((transpose(transpose(X,4) ,-5) |shuffle((transpose(transpose(X,-7) ,-7) +shuffle(X) ) ) ) ,12) +transpose(shuffle(echo(X,4,6) ) ,12) ) +transpose(transpose((((transpose((X+X) ,4) +transpose(echo(transpose(((X+transpose(X,4) ) +transpose(X,7) ) ,-7) ,4,6) ,4) ) +transpose(((X+transpose(((X+transpose(X,4) ) +transpose(X,7) ) ,12) ) |shuffle(X) ) ,7) ) +(shuffle((step(X,12) +transpose(X,7) ) ) +((X+(X+X) ) +transpose((X+step(X,12) ) ,12) ) ) ) ,-5) ,12) ) +(transpose((((transpose(transpose(transpose((X|X) ,-7) ,4) ,-7) +transpose((X+X) ,4) ) +transpose(transpose(X,-5) ,7) ) +transpose((arpeggio((transpose(echo(X,4,6) ,-7) |((X+transpose(X,12) ) +(X+X) ) ) ) +transpose(X,-5) ) ,12) ) ,-5) +transpose(transpose((((X+transpose((X+transpose(X,7) ) ,12) ) +(X+transpose(X,12) ) ) |(transpose(X,4) +transpose(echo(X,4,6) ,12) ) ) ,-5) ,7) ) ) ) ,-7) ,7) ) ,7) ) ,-7) +transpose(shuffle(((transpose(((transpose((((((transpose(X,-7) +transpose(transpose(((X|X) +transpose(((X+transpose(X,4) ) +transpose(X,7) ) ,12) ) ,4) ,4) ) +transpose(X,7) ) +echo(((X+transpose(X,12) ) +transpose(shuffle(transpose(X,-5) ) ,7) ) ,4,6) ) +transpose(((X|X) +transpose((arpeggio(transpose(X,-5) ) +step((X|X) ,12) ) ,12) ) ,4) ) +transpose(transpose(step(step(transpose(X,-7) ,12) ,12) ,4) ,7) ) ,-5) +transpose(((arpeggio((transpose((step(arpeggio(X) ,12) |transpose(X,-7) ) ,-7) +arpeggio((X+transpose(shuffle(X) ,7) ) ) ) ) |echo(transpose((transpose(X,-5) |transpose(X,-7) ) ,4) ,4,6) ) +transpose(transpose(((X|X) +transpose(step(X,12) ,12) ) ,4) ,-7) ) ,4) ) +transpose((echo((((transpose(X,4) |X) +transpose(echo((X+transpose(X,7) ) ,4,6) ,4) ) +transpose(echo(arpeggio(X) ,4,6) ,7) ) ,4,6) |step(echo((X+X) ,4,6) ,12) ) ,7) ) ,-5) +shuffle(step(echo(transpose(transpose(step((X+transpose(X,7) ) ,12) ,-7) ,-5) ,4,6) ,12) ) ) +(step((((transpose(step(transpose((((X+transpose(X,4) ) +transpose(X,7) ) +((transpose(X,-5) +transpose((X+X) ,4) ) +transpose(((X+transpose(X,12) ) +(X+transpose(X,7) ) ) ,7) ) ) ,-5) ,12) ,-5) +transpose(transpose(echo(transpose(step(step(X,12) ,12) ,4) ,4,6) ,-7) ,4) ) +transpose(transpose(echo(step(step(shuffle(X) ,12) ,12) ,4,6) ,-7) ,7) ) +(transpose(arpeggio(shuffle((X+X) ) ) ,-7) +arpeggio(transpose((shuffle(transpose(transpose(X,4) ,4) ) +transpose(transpose((((X+transpose(X,4) ) +transpose(X,7) ) +X) ,4) ,4) ) ,4) ) ) ) ,12) +(transpose(((X+transpose(X,7) ) |step((((X+shuffle(X) ) +transpose(transpose(X,-5) ,12) ) |transpose(X,4) ) ,12) ) ,-5) +transpose(((((shuffle(step(X,12) ) +(((transpose(shuffle(X) ,-5) +transpose(transpose(step(X,12) ,-7) ,12) ) +transpose(step(X,12) ,4) ) +transpose(transpose(((X+transpose(X,7) ) +X) ,4) ,7) ) ) |echo(shuffle(transpose(X,4) ) ,4,6) ) +transpose(arpeggio((((transpose((transpose((echo(X,4,6) +transpose(echo(X,4,6) ,12) ) ,-7) +transpose((transpose(X,4) +transpose(shuffle(X) ,12) ) ,12) ) ,4) +transpose(transpose(((X+transpose(((X+transpose(X,4) ) +transpose(X,7) ) ,12) ) |((X+transpose(transpose(X,4) ,4) ) +transpose(X,7) ) ) ,-5) ,4) ) +transpose(transpose((((X+transpose(X,12) ) +X) +((X+transpose(X,12) ) +transpose(transpose(X,-5) ,12) ) ) ,4) ,7) ) +transpose(transpose(((arpeggio(X) +transpose(((transpose(X,-7) +((X+transpose(X,4) ) +transpose(X,7) ) ) +(arpeggio(X) |(X|X) ) ) ,7) ) |(((X+(X|X) ) +transpose(step(X,12) ,7) ) +step(step(step(X,12) ,12) ,12) ) ) ,4) ,7) ) ) ,4) ) +transpose((((shuffle(shuffle(X) ) +transpose((X+X) ,7) ) +(X+transpose((X+transpose(X,12) ) ,-7) ) ) +transpose((transpose((arpeggio(X) +(X+transpose(X,7) ) ) ,-5) +transpose(transpose((X+transpose(X,7) ) ,4) ,12) ) ,7) ) ,7) ) ,12) ) ) ) ) ,4) ) +transpose(transpose(((((((transpose(transpose(arpeggio((X|X) ) ,-7) ,-7) |arpeggio((X+transpose(X,7) ) ) ) +transpose(((step(X,12) +transpose(X,7) ) |(((X|X) +transpose(transpose(X,-5) ,12) ) +transpose(transpose(X,-5) ,12) ) ) ,4) ) +transpose((arpeggio((step((step(step(X,12) ,12) +transpose(((X+transpose(transpose(X,4) ,4) ) +transpose(transpose(X,-7) ,7) ) ,7) ) ,12) +transpose(transpose((transpose(transpose(((arpeggio(X) +X) +((X|X) |transpose(X,4) ) ) ,4) ,4) |(shuffle((((transpose(X,-5) |transpose(X,-5) ) +transpose(transpose(X,4) ,4) ) +transpose((X+transpose(transpose(X,-7) ,7) ) ,7) ) ) +(transpose((X+echo(X,4,6) ) ,-5) +transpose(transpose(X,-7) ,12) ) ) ) ,-7) ,12) ) ) +transpose((arpeggio(((X|X) +transpose(step(X,12) ,7) ) ) |((arpeggio(((X+transpose(X,7) ) +transpose((X+transpose(X,12) ) ,12) ) ) +echo(transpose(arpeggio((echo(X,4,6) +X) ) ,-7) ,4,6) ) +(((step(((X+transpose(X,4) ) +transpose(X,7) ) ,12) +(shuffle((X+transpose(X,12) ) ) |arpeggio(transpose(X,4) ) ) ) +transpose(arpeggio(transpose(transpose(X,-5) ,-7) ) ,4) ) +transpose(transpose((X|X) ,4) ,7) ) ) ) ,12) ) ,7) ) +((((transpose(((transpose(transpose(X,4) ,-7) +transpose(X,7) ) +transpose((transpose((((transpose(X,-5) +((X+transpose(X,7) ) +transpose(X,4) ) ) +transpose(arpeggio(transpose(X,-7) ) ,4) ) +transpose(transpose((X+transpose((X+transpose(X,7) ) ,7) ) ,-7) ,7) ) ,-5) |step(X,12) ) ,7) ) ,-7) +transpose(((((arpeggio((transpose(transpose((X+X) ,-7) ,-5) +transpose(transpose(echo((X+transpose(transpose(X,-5) ,12) ) ,4,6) ,4) ,12) ) ) +transpose((echo((step(X,12) +transpose(echo(X,4,6) ,7) ) ,4,6) +transpose((arpeggio(((X+transpose(X,4) ) +transpose(X,7) ) ) +shuffle(X) ) ,12) ) ,4) ) +transpose(echo((step((echo(X,4,6) |X) ,12) +transpose(transpose(X,4) ,4) ) ,4,6) ,7) ) +transpose(echo((transpose((transpose(X,4) +transpose(transpose(X,4) ,12) ) ,-5) |((transpose(X,-7) +transpose(transpose(X,-7) ,12) ) |transpose((X+transpose(X,12) ) ,-7) ) ) ,4,6) ,4) ) +transpose((arpeggio(echo(transpose(transpose((transpose(X,-7) +transpose((X|X) ,12) ) ,-7) ,-7) ,4,6) ) +transpose(transpose(transpose((transpose(step(X,12) ,-7) |((X+transpose(X,12) ) |transpose(X,4) ) ) ,-5) ,-5) ,12) ) ,7) ) ,12) ) +transpose((((X+transpose(transpose(X,-7) ,4) ) +transpose(transpose(X,4) ,7) ) +transpose(((transpose(step(X,12) ,4) +transpose((X|X) ,4) ) +transpose(step(transpose(X,-7) ,12) ,7) ) ,7) ) ,-5) ) +transpose((transpose(((arpeggio(echo(transpose(X,4) ,4,6) ) +transpose(X,7) ) +transpose((transpose(X,-5) +transpose((X+transpose(X,7) ) ,4) ) ,7) ) ,4) +transpose(shuffle(((echo((((transpose(echo(X,4,6) ,4) +arpeggio(shuffle((X+transpose(X,7) ) ) ) ) +transpose((transpose(shuffle(X) ,-5) +transpose((X+transpose(transpose(X,-7) ,7) ) ,12) ) ,4) ) +transpose(transpose(shuffle(X) ,-5) ,7) ) ,4,6) +transpose(echo((((transpose(echo(X,4,6) ,4) +transpose(transpose(X,4) ,7) ) +transpose(echo(step(X,12) ,4,6) ,-7) ) |(X+transpose(transpose(X,-7) ,7) ) ) ,4,6) ,4) ) +transpose((transpose((arpeggio(arpeggio(arpeggio(X) ) ) +transpose((((X+transpose(X,4) ) +transpose(X,7) ) +(X|X) ) ,4) ) ,-7) +(arpeggio(transpose(((X+X) +transpose((X+X) ,7) ) ,-7) ) |((transpose(transpose(arpeggio(step(shuffle(X) ,12) ) ,4) ,-5) +transpose((transpose(transpose(transpose(X,-7) ,-7) ,-5) |transpose(((X+transpose((X|X) ,12) ) +transpose(X,-7) ) ,-5) ) ,4) ) +transpose((((X|X) +X) +transpose(arpeggio(X) ,12) ) ,7) ) ) ) ,7) ) ) ,12) ) ,4) ) +transpose(echo((transpose(((shuffle(arpeggio(X) ) +transpose((X+transpose(X,7) ) ,12) ) +transpose(transpose(transpose((X|X) ,-7) ,-5) ,12) ) ,-5) +transpose(arpeggio(echo(((((shuffle(X) +X) +transpose(arpeggio((X+X) ) ,4) ) +transpose(X,7) ) +transpose(echo(X,4,6) ,4) ) ,4,6) ) ,12) ) ,4,6) ,7) ) ) +shuffle((transpose(arpeggio((X+X) ) ,-5) +transpose(transpose(transpose(arpeggio((transpose(transpose(((X+transpose(X,12) ) |X) ,4) ,4) +transpose(transpose(X,4) ,7) ) ) ,-7) ,-5) ,-5) ) ) ) +((transpose(((((echo((transpose(X,-5) +transpose(((X+transpose(X,4) ) +transpose(X,7) ) ,12) ) ,4,6) +transpose(transpose(shuffle(step(X,12) ) ,-7) ,7) ) +transpose(transpose(transpose(((X+transpose(X,4) ) +transpose(X,7) ) ,-5) ,4) ,12) ) +arpeggio(((X+transpose(transpose((X+X) ,-5) ,7) ) +transpose(echo(((X+transpose((X|X) ,4) ) +transpose(transpose(X,-5) ,7) ) ,4,6) ,12) ) ) ) +transpose(transpose(transpose(transpose((transpose(arpeggio((X+transpose(shuffle(X) ,7) ) ) ,-5) +step((transpose(X,4) |X) ,12) ) ,4) ,4) ,4) ,7) ) ,-5) |transpose((echo((arpeggio((((X+transpose(X,7) ) +transpose(X,4) ) +transpose(echo(transpose(X,4) ,4,6) ,7) ) ) +arpeggio(X) ) ,4,6) +transpose(transpose(transpose(transpose(transpose((transpose(transpose(transpose(X,-7) ,4) ,-7) |((X|arpeggio((X+transpose(X,12) ) ) ) +arpeggio(X) ) ) ,-5) ,-7) ,-5) ,4) ,12) ) ,-5) ) +transpose((shuffle(transpose((echo((X+X) ,4,6) |(X+transpose(X,4) ) ) ,-5) ) +transpose(((transpose((((arpeggio(transpose((X|X) ,-5) ) +transpose(transpose(((X+transpose(X,7) ) |X) ,4) ,7) ) +transpose(transpose((shuffle(step(X,12) ) +transpose(echo(X,4,6) ,12) ) ,-7) ,4) ) +transpose(transpose(X,-7) ,7) ) ,-7) +transpose(transpose(transpose((transpose(((arpeggio(X) +transpose(X,4) ) +transpose(X,7) ) ,-5) +(((X+transpose(X,7) ) |transpose(X,-5) ) +transpose(X,4) ) ) ,-5) ,4) ,4) ) +transpose((((transpose(echo(X,4,6) ,-7) +transpose(X,12) ) +transpose(((((shuffle(X) +((X+transpose(X,4) ) +transpose(X,7) ) ) |(((X+transpose(X,4) ) +transpose(X,7) ) +transpose(transpose(X,-5) ,12) ) ) +transpose(((((X+transpose(transpose(X,-5) ,4) ) +transpose(X,7) ) +transpose(step(X,12) ,4) ) +transpose((transpose(X,-5) +transpose((X+X) ,12) ) ,7) ) ,12) ) +((transpose(X,-5) +X) +transpose(transpose(shuffle(X) ,4) ,7) ) ) ,12) ) +transpose(transpose(shuffle(transpose(X,4) ) ,-5) ,7) ) ,7) ) ,7) ) ,7) ) ) ,-7) ,7) ) ,7) ) )
random seed used was 217486272

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