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:
(((transpose((echo((transpose((((arpeggio((((transpose(arpeggio(arpeggio(X) ) ,-7) |(transpose(shuffle(X) ,-5) |step(transpose(X,-7) ,12) ) ) +transpose(shuffle(shuffle(transpose((X|X) ,4) ) ) ,12) ) +transpose(shuffle(step(transpose(X,-5) ,12) ) ,4) ) ) +transpose((transpose((shuffle(arpeggio(X) ) +(transpose(arpeggio(X) ,4) +transpose(X,7) ) ) ,-5) +transpose((X+X) ,12) ) ,4) ) +transpose(shuffle(shuffle((arpeggio(transpose((X+transpose(X,7) ) ,-5) ) |step((X+X) ,12) ) ) ) ,7) ) +transpose(transpose(transpose(arpeggio((X+transpose(X,12) ) ) ,4) ,-5) ,7) ) ,-7) +transpose(((step(transpose((echo(arpeggio(transpose((X+X) ,-5) ) ,4,6) +transpose((transpose(X,4) |transpose(shuffle(X) ,-5) ) ,12) ) ,4) ,12) +shuffle(transpose(transpose((shuffle(transpose(transpose(X,-5) ,4) ) +transpose((step((shuffle(X) +transpose(X,12) ) ,12) +X) ,12) ) ,4) ,-7) ) ) +((((echo(shuffle(shuffle(X) ) ,4,6) +transpose((((X+X) +X) +transpose(transpose(X,-7) ,12) ) ,4) ) +transpose(echo(shuffle(shuffle((X+X) ) ) ,4,6) ,7) ) +transpose((arpeggio(transpose(transpose(X,4) ,-5) ) +transpose(((shuffle((shuffle(X) |echo((X+X) ,4,6) ) ) +transpose((((((X|transpose(X,4) ) +transpose(step(shuffle(X) ,12) ,4) ) +transpose((X+transpose(transpose(X,-7) ,12) ) ,7) ) +transpose(transpose(echo(X,4,6) ,4) ,4) ) +transpose(arpeggio(X) ,7) ) ,4) ) +transpose(echo(transpose(X,-7) ,4,6) ,7) ) ,7) ) ,12) ) +arpeggio(shuffle(((arpeggio(arpeggio(X) ) +transpose(echo(echo(X,4,6) ,4,6) ,4) ) +transpose(X,7) ) ) ) ) ) ,12) ) ,4,6) |arpeggio(echo(echo(shuffle(transpose(transpose((X|((X+transpose(X,4) ) +transpose(X,7) ) ) ,4) ,4) ) ,4,6) ,4,6) ) ) ,-5) +transpose((arpeggio(transpose(arpeggio(((((((X+transpose(X,12) ) +shuffle(X) ) +arpeggio(transpose((transpose(X,-5) +transpose((X|X) ,7) ) ,-5) ) ) |transpose((transpose(transpose(transpose(X,4) ,-5) ,-7) +transpose(echo((X+transpose(X,12) ) ,4,6) ,-7) ) ,4) ) |((transpose(arpeggio(X) ,4) +X) +X) ) +transpose(((shuffle(((shuffle(shuffle((X+X) ) ) +step(X,12) ) +(shuffle(X) |shuffle((X+transpose(X,7) ) ) ) ) ) +transpose(echo(((echo(X,4,6) +transpose(echo((X|X) ,4,6) ,7) ) +(transpose(X,-5) |X) ) ,4,6) ,4) ) +transpose(transpose(echo((shuffle(X) +transpose((transpose(echo(X,4,6) ,-7) +transpose(transpose(X,-5) ,-5) ) ,7) ) ,4,6) ,-5) ,7) ) ,7) ) ) ,-5) ) +transpose(arpeggio(transpose((shuffle(shuffle(step(X,12) ) ) |step(shuffle(((arpeggio(X) +transpose(arpeggio((X+transpose(X,7) ) ) ,4) ) +transpose(transpose(transpose(X,4) ,4) ,7) ) ) ,12) ) ,4) ) ,-7) ) ,7) ) +transpose(((shuffle((arpeggio((transpose(arpeggio(transpose(shuffle(transpose(arpeggio(shuffle(step(X,12) ) ) ,4) ) ,-7) ) ,-7) +(shuffle(arpeggio(shuffle((arpeggio((X+transpose(X,7) ) ) +(arpeggio(transpose(((X+transpose(X,12) ) |echo(X,4,6) ) ,-5) ) +transpose(transpose(shuffle(arpeggio(X) ) ,4) ,12) ) ) ) ) ) +(arpeggio(transpose((arpeggio((X+transpose(X,7) ) ) +arpeggio(shuffle(arpeggio(transpose(X,4) ) ) ) ) ,-5) ) +transpose(arpeggio(transpose(transpose(X,-5) ,4) ) ,4) ) ) ) ) +transpose(transpose(transpose(((((((step(arpeggio(shuffle(arpeggio((X|X) ) ) ) ,12) +transpose(arpeggio(echo((X+X) ,4,6) ) ,4) ) +transpose((arpeggio((((((X+transpose(X,4) ) +transpose(X,7) ) +transpose(echo(X,4,6) ,12) ) +arpeggio((transpose(X,4) |X) ) ) +transpose(arpeggio((X+transpose(X,7) ) ) ,7) ) ) +transpose((((X+transpose(X,4) ) +transpose(X,7) ) +transpose(echo(X,4,6) ,12) ) ,12) ) ,7) ) +transpose(echo(echo((transpose(X,-5) +transpose(transpose(transpose(X,-5) ,4) ,12) ) ,4,6) ,4,6) ,-5) ) +transpose(((transpose(transpose((((transpose(X,-7) +transpose((X+transpose(X,12) ) ,7) ) |(X+transpose(X,12) ) ) +transpose((X+transpose(transpose(transpose(X,-7) ,-5) ,7) ) ,7) ) ,-7) ,4) +transpose(arpeggio(transpose(((transpose(transpose(transpose((transpose(X,4) |X) ,-5) ,-7) ,-5) +transpose((X+transpose(transpose((X|X) ,-5) ,12) ) ,-7) ) +transpose((transpose(shuffle((X+X) ) ,-5) +step(X,12) ) ,12) ) ,-7) ) ,7) ) |echo(step((transpose(shuffle(((transpose(X,-7) +transpose(X,4) ) +transpose(transpose(X,-7) ,7) ) ) ,-7) +transpose(transpose(echo(X,4,6) ,4) ,-7) ) ,12) ,4,6) ) ,4) ) +transpose(transpose((arpeggio(arpeggio(transpose(transpose(shuffle(X) ,4) ,-5) ) ) |transpose((((echo(X,4,6) +transpose((X|arpeggio(X) ) ,12) ) |(((X+X) +transpose(transpose(step(X,12) ,-5) ,4) ) +transpose(arpeggio(X) ,7) ) ) +transpose(shuffle(((X+(X+(X+X) ) ) |transpose(shuffle(X) ,4) ) ) ,7) ) ,4) ) ,4) ,7) ) |transpose(transpose(transpose(transpose(arpeggio((arpeggio(shuffle((X|X) ) ) +(transpose(X,-5) |(X|transpose(X,-5) ) ) ) ) ,-7) ,-5) ,4) ,-7) ) ,4) ,4) ,7) ) ) +transpose(step(transpose(echo((transpose(transpose((X+(transpose(X,4) +transpose(transpose((X|X) ,4) ,7) ) ) ,-5) ,-5) |transpose(((((transpose((transpose(X,-7) |X) ,4) +transpose(shuffle(((X+transpose(X,4) ) +transpose(X,7) ) ) ,7) ) +transpose(((X+transpose(X,-7) ) +transpose(transpose(transpose(echo(X,4,6) ,-7) ,4) ,7) ) ,4) ) +transpose(shuffle(transpose(shuffle(((X+transpose(X,7) ) +transpose(transpose((X+X) ,4) ,12) ) ) ,-5) ) ,7) ) +transpose(transpose(step((transpose(arpeggio(transpose(X,-7) ) ,-7) +transpose(((((X|X) +transpose(shuffle(X) ,4) ) +transpose((X+X) ,7) ) +transpose(arpeggio(X) ,12) ) ,7) ) ,12) ,-5) ,12) ) ,-5) ) ,4,6) ,4) ,12) ,4) ) +transpose(transpose(echo(((arpeggio(arpeggio(((transpose(transpose(transpose(arpeggio(X) ,4) ,4) ,-5) +transpose((transpose((X|(arpeggio(X) +X) ) ,4) +transpose(echo((transpose(arpeggio(X) ,4) +echo(X,4,6) ) ,4,6) ,7) ) ,4) ) +transpose((transpose((((X+transpose(X,7) ) +transpose(arpeggio(X) ,4) ) +transpose(X,7) ) ,-5) +transpose(arpeggio(transpose(transpose(X,4) ,-5) ) ,12) ) ,7) ) ) ) +((transpose(arpeggio(step(transpose(X,-5) ,12) ) ,-5) +transpose(echo(transpose(transpose(transpose((shuffle(shuffle(X) ) |arpeggio((X|X) ) ) ,-5) ,-7) ,-5) ,4,6) ,7) ) |((echo((transpose((((X+(X+X) ) +transpose(arpeggio(arpeggio(((X+transpose(X,4) ) +transpose(X,7) ) ) ) ,12) ) |transpose(transpose(X,4) ,-5) ) ,4) +transpose(arpeggio(arpeggio((transpose(transpose(arpeggio(X) ,-5) ,-5) +transpose(transpose(X,-5) ,12) ) ) ) ,12) ) ,4,6) +transpose((step(transpose(arpeggio(shuffle(X) ) ,-7) ,12) +transpose(transpose((shuffle(X) |(((X|X) +(X|X) ) |shuffle((X+transpose(X,12) ) ) ) ) ,4) ,4) ) ,12) ) +(echo(transpose((((shuffle(transpose(X,-7) ) |step(transpose(X,-5) ,12) ) +transpose(transpose(transpose(step(X,12) ,-7) ,4) ,4) ) +transpose((echo(echo(X,4,6) ,4,6) +transpose(arpeggio(X) ,12) ) ,7) ) ,-7) ,4,6) +transpose(shuffle((shuffle(((((((X+X) +transpose(step((X+X) ,12) ,4) ) +transpose(arpeggio(X) ,7) ) +transpose(transpose((X+transpose(X,7) ) ,-7) ,4) ) +transpose((arpeggio(transpose(X,4) ) |transpose(X,-7) ) ,7) ) +step(shuffle(X) ,12) ) ) +transpose((((transpose(transpose(shuffle(step(X,12) ) ,-5) ,-5) +(step(transpose(X,-5) ,12) +(shuffle(step(X,12) ) +transpose((transpose(X,4) +X) ,12) ) ) ) +transpose(arpeggio(arpeggio(transpose(X,-5) ) ) ,4) ) +transpose(X,7) ) ,12) ) ) ,7) ) ) ) ) +transpose((transpose(((((step(arpeggio(X) ,12) |arpeggio((((X+transpose(X,7) ) +X) |X) ) ) +transpose(((shuffle(echo(arpeggio(X) ,4,6) ) +transpose(((transpose(transpose(X,4) ,4) +transpose(X,4) ) +transpose(arpeggio((X+transpose(transpose(X,-5) ,12) ) ) ,7) ) ,4) ) +transpose(arpeggio((step(X,12) +transpose((X|X) ,12) ) ) ,7) ) ,7) ) +transpose(echo((step(step(transpose((X+X) ,-7) ,12) ,12) +transpose(arpeggio(X) ,-7) ) ,4,6) ,12) ) +transpose(arpeggio(arpeggio(((transpose(X,-5) +transpose(transpose(X,-5) ,7) ) +transpose(arpeggio(arpeggio(X) ) ,-7) ) ) ) ,7) ) ,-5) +transpose((transpose(arpeggio(((shuffle(transpose(transpose(X,-7) ,4) ) +transpose(transpose(((X+transpose(X,4) ) +transpose(X,7) ) ,-7) ,4) ) +transpose(step(X,12) ,7) ) ) ,-5) |shuffle(((arpeggio(arpeggio((shuffle(X) +arpeggio(echo(X,4,6) ) ) ) ) +transpose(transpose(((X+X) |(transpose(X,4) +(X+transpose(X,7) ) ) ) ,4) ,4) ) +transpose((transpose((X+transpose(X,7) ) ,-5) +transpose(shuffle(step(X,12) ) ,7) ) ,7) ) ) ) ,-5) ) ,7) ) ,4,6) ,-5) ,7) ) ,4) ) +transpose(((((echo(arpeggio(transpose(transpose((step(echo(shuffle(((X+transpose(X,4) ) +transpose(X,7) ) ) ,4,6) ,12) +step(transpose((shuffle(X) |X) ,4) ,12) ) ,-7) ,-7) ) ,4,6) +transpose(shuffle(transpose((arpeggio(arpeggio(arpeggio((echo((((X+X) |X) +((X+X) +transpose((X+transpose(X,7) ) ,7) ) ) ,4,6) +((transpose(arpeggio(((X+transpose(X,4) ) +transpose(X,7) ) ) ,-5) +transpose(arpeggio((X+transpose(X,7) ) ) ,4) ) +transpose((shuffle((transpose(X,-5) +transpose(X,12) ) ) |transpose(((X|X) |transpose(X,4) ) ,4) ) ,7) ) ) ) ) ) |transpose(((((transpose(arpeggio(echo(X,4,6) ) ,-5) +transpose(shuffle(transpose(step(shuffle(X) ,12) ,-5) ) ,7) ) +transpose(arpeggio(((((X+shuffle(X) ) +shuffle(X) ) +transpose(shuffle(arpeggio(X) ) ,4) ) +transpose(((X|X) +transpose((X|X) ,7) ) ,7) ) ) ,12) ) |(step((((transpose(X,-5) |step(X,12) ) +transpose(transpose(X,-7) ,12) ) +transpose(shuffle(((X+transpose(X,4) ) +transpose(X,7) ) ) ,7) ) ,12) +transpose(transpose(transpose((transpose(arpeggio(shuffle(X) ) ,4) |(arpeggio(((X+transpose(X,4) ) +transpose(X,7) ) ) |transpose(echo(X,4,6) ,-5) ) ) ,4) ,-7) ,12) ) ) +transpose(transpose(shuffle((((X+transpose(transpose(X,-5) ,4) ) +transpose(((X+transpose(X,4) ) +transpose(X,7) ) ,7) ) +transpose(transpose(X,4) ,12) ) ) ,-7) ,12) ) ,-7) ) ,4) ) ,7) ) +transpose(transpose(shuffle(arpeggio((echo((transpose(X,4) +transpose(transpose(X,-5) ,12) ) ,4,6) +arpeggio((arpeggio(X) +transpose(X,-7) ) ) ) ) ) ,4) ,4) ) +transpose((step(transpose(step(((((arpeggio(transpose(transpose(arpeggio(((X+transpose((X+X) ,12) ) +transpose(((X+transpose(arpeggio(X) ,4) ) +transpose(((X+transpose(X,4) ) +transpose(X,7) ) ,7) ) ,7) ) ) ,4) ,4) ) +transpose(transpose(echo((shuffle(X) +X) ,4,6) ,4) ,7) ) +transpose((transpose(transpose(step((arpeggio(X) +transpose((X+X) ,12) ) ,12) ,-5) ,4) +transpose(transpose((shuffle(X) +((((((X+X) +transpose(transpose(X,4) ,4) ) +transpose(echo(X,4,6) ,7) ) +transpose(shuffle((X+transpose(X,12) ) ) ,7) ) +transpose((transpose(shuffle(X) ,-5) |X) ,4) ) +transpose(X,7) ) ) ,4) ,12) ) ,4) ) +step((arpeggio((step(shuffle((X+transpose(X,12) ) ) ,12) +(arpeggio((X+transpose(X,7) ) ) |transpose(X,-7) ) ) ) +(((transpose(step(X,12) ,-5) +(transpose(X,4) +transpose((transpose(X,-5) +(X+X) ) ,12) ) ) +transpose(step(shuffle(shuffle(X) ) ,12) ,4) ) +transpose((transpose(transpose(shuffle(X) ,4) ,-5) |arpeggio(arpeggio((step(X,12) |shuffle((X+transpose(X,12) ) ) ) ) ) ) ,7) ) ) ,12) ) +arpeggio(shuffle(echo(((shuffle(X) +transpose(shuffle(X) ,7) ) +transpose((X+transpose(X,7) ) ,-5) ) ,4,6) ) ) ) ,12) ,-7) ,12) +transpose((transpose(((transpose((transpose(echo(X,4,6) ,-7) |shuffle(arpeggio(transpose(arpeggio(X) ,4) ) ) ) ,4) +transpose(arpeggio(echo(shuffle(X) ,4,6) ) ,4) ) +transpose(step(transpose((X+transpose(X,12) ) ,-5) ,12) ,7) ) ,4) +echo(arpeggio((shuffle((((step(arpeggio((transpose(X,-5) +transpose((transpose(X,4) |(X|X) ) ,4) ) ) ,12) +transpose(transpose(shuffle((transpose(arpeggio((X|shuffle(X) ) ) ,-5) +transpose(transpose((echo((X+X) ,4,6) +transpose(shuffle(X) ,7) ) ,-5) ,12) ) ) ,4) ,4) ) +transpose(step(transpose(echo(((X+transpose(X,12) ) +transpose(((arpeggio(X) |(arpeggio(X) |X) ) +transpose((step(X,12) +echo(X,4,6) ) ,12) ) ,7) ) ,4,6) ,-5) ,12) ,7) ) |transpose(shuffle(arpeggio(arpeggio((((X+transpose(arpeggio(X) ,12) ) +transpose((X+transpose(X,7) ) ,4) ) +arpeggio(arpeggio(X) ) ) ) ) ) ,4) ) ) +(transpose(transpose((transpose(transpose(((X+transpose(step(arpeggio(X) ,12) ,4) ) +transpose(shuffle((X+X) ) ,7) ) ,4) ,4) |arpeggio(transpose((X+transpose(X,7) ) ,-7) ) ) ,-7) ,-5) |((shuffle(transpose((X+transpose(X,12) ) ,-5) ) +arpeggio(transpose(arpeggio(((X+transpose(X,12) ) +transpose(X,12) ) ) ,4) ) ) |(((((step(transpose(X,-7) ,12) +transpose((X|X) ,12) ) +transpose(transpose(X,-7) ,4) ) +transpose((((X+X) +transpose((X|(X+X) ) ,7) ) +(shuffle(X) |X) ) ,7) ) +transpose(arpeggio(transpose(X,-5) ) ,4) ) +transpose(((arpeggio(X) +transpose(X,4) ) |arpeggio((X|X) ) ) ,7) ) ) ) ) ) ,4,6) ) ,7) ) ,12) ) +(shuffle((shuffle((shuffle(transpose(arpeggio(transpose(((((echo(((X+transpose(X,12) ) |(X+transpose(X,7) ) ) ,4,6) +transpose(step(X,12) ,4) ) +transpose((transpose(echo(((X+transpose(X,4) ) +transpose(X,7) ) ,4,6) ,4) +(X+transpose(transpose(X,-5) ,12) ) ) ,7) ) |transpose(transpose((X|X) ,4) ,4) ) +transpose(transpose(arpeggio(((X+X) |arpeggio(X) ) ) ,-5) ,7) ) ,-5) ) ,-7) ) +transpose(shuffle((transpose((shuffle(shuffle(step(X,12) ) ) +echo(transpose(arpeggio(X) ,-7) ,4,6) ) ,4) +transpose(transpose(arpeggio(((arpeggio(X) +transpose(arpeggio(X) ,12) ) +transpose(shuffle((arpeggio(X) +X) ) ,7) ) ) ,4) ,4) ) ) ,4) ) ) |shuffle(echo((((transpose((step(step(transpose(step(shuffle(X) ,12) ,-7) ,12) ,12) |shuffle(transpose(transpose(echo(transpose(X,4) ,4,6) ,4) ,-5) ) ) ,-5) +transpose(transpose(transpose(shuffle((transpose(transpose(step((((shuffle(X) |X) +transpose(X,4) ) +transpose(((transpose(X,4) +transpose(transpose(X,4) ,4) ) +transpose((X+X) ,7) ) ,7) ) ,12) ,4) ,4) +(transpose((X+transpose(arpeggio(X) ,12) ) ,-5) |(arpeggio((arpeggio(X) +transpose(shuffle(transpose(X,-5) ) ,7) ) ) +transpose(((((X+transpose(X,7) ) +transpose((X+transpose(X,12) ) ,4) ) +transpose(step(X,12) ,7) ) +transpose(arpeggio(X) ,-5) ) ,7) ) ) ) ) ,4) ,4) ,12) ) +transpose((transpose(shuffle((arpeggio(echo(X,4,6) ) +X) ) ,-5) +transpose((shuffle(echo(step((shuffle(X) +transpose(transpose(X,-5) ,7) ) ,12) ,4,6) ) +transpose((((transpose(transpose(X,4) ,4) +transpose(transpose(shuffle(X) ,4) ,7) ) +transpose(arpeggio(X) ,7) ) |(echo(shuffle(X) ,4,6) |(shuffle(arpeggio(X) ) +transpose(((X+transpose(X,4) ) +transpose(X,7) ) ,7) ) ) ) ,12) ) ,-7) ) ,4) ) +transpose((transpose((shuffle((((transpose(X,4) +transpose((X|X) ,12) ) +transpose(((X|X) +transpose((X+transpose(X,12) ) ,12) ) ,12) ) |echo(X,4,6) ) ) +transpose(shuffle(shuffle(step(transpose((X|X) ,4) ,12) ) ) ,7) ) ,-7) +transpose((step((((shuffle(arpeggio(step(X,12) ) ) +((X+transpose(X,12) ) +transpose(((X+transpose(arpeggio(X) ,4) ) +transpose(echo(X,4,6) ,7) ) ,7) ) ) +transpose(transpose(transpose(X,-5) ,-7) ,4) ) +transpose((((arpeggio(arpeggio(X) ) +transpose((X+transpose(X,7) ) ,12) ) +transpose(((X+transpose(X,12) ) +shuffle(arpeggio(X) ) ) ,4) ) +transpose(echo(arpeggio(X) ,4,6) ,7) ) ,7) ) ,12) +transpose(echo(echo(arpeggio((transpose((step(X,12) +shuffle(X) ) ,-7) +arpeggio(arpeggio(shuffle(X) ) ) ) ) ,4,6) ,4,6) ,12) ) ,12) ) ,7) ) ,4,6) ) ) ) +transpose(((shuffle((((shuffle((transpose(arpeggio(((X+(X+transpose(X,12) ) ) |transpose(transpose(X,-5) ,-5) ) ) ,-7) +(transpose(transpose(arpeggio(X) ,4) ,-5) |((X|shuffle(X) ) +transpose(((transpose(X,-7) +transpose(X,-7) ) +transpose(arpeggio(shuffle((X+transpose(X,7) ) ) ) ,12) ) ,7) ) ) ) ) +transpose(echo(shuffle((transpose(transpose(X,-5) ,-5) +(((X+X) |X) |step(X,12) ) ) ) ,4,6) ,12) ) +shuffle(echo(echo((shuffle(X) +(X|arpeggio(X) ) ) ,4,6) ,4,6) ) ) +transpose((transpose((X|transpose(X,4) ) ,-7) +step(((arpeggio(((arpeggio(((X+transpose(shuffle(arpeggio(transpose(X,-5) ) ) ,4) ) +transpose((arpeggio(X) +transpose(echo(X,4,6) ,12) ) ,7) ) ) +transpose(((transpose(X,4) +transpose(transpose(X,-5) ,7) ) |arpeggio((X|transpose((X|X) ,-5) ) ) ) ,4) ) +transpose(shuffle(((step(((X+transpose(X,4) ) +transpose(X,7) ) ,12) |transpose((X+transpose(X,12) ) ,4) ) +transpose((X+X) ,12) ) ) ,7) ) ) |((transpose(shuffle(transpose(X,-7) ) ,-5) +transpose(arpeggio(arpeggio(echo(((X+transpose(X,7) ) |shuffle(X) ) ,4,6) ) ) ,12) ) |((transpose(X,4) +(transpose((transpose(X,-7) +transpose(X,7) ) ,-5) +(echo(X,4,6) +transpose(X,7) ) ) ) |((step(X,12) |echo(arpeggio(X) ,4,6) ) +shuffle(((X+X) +X) ) ) ) ) ) +transpose(((arpeggio((X+X) ) |step(shuffle((X|X) ) ,12) ) +transpose(transpose(X,4) ,7) ) ,12) ) ,12) ) ,7) ) ) +transpose(((((echo(((transpose((X+transpose(X,12) ) ,-5) +transpose(transpose(transpose((X+transpose(X,12) ) ,-5) ,4) ,7) ) +transpose(echo(arpeggio(X) ,4,6) ,4) ) ,4,6) +transpose((transpose(((((X+transpose(X,12) ) +arpeggio(X) ) +transpose(arpeggio(transpose((X+transpose(X,7) ) ,4) ) ,4) ) +transpose(((step(X,12) +transpose(X,12) ) +transpose(shuffle(arpeggio(X) ) ,7) ) ,7) ) ,-7) +transpose(shuffle(arpeggio(((shuffle(((X+transpose(transpose(X,-5) ,12) ) +transpose(X,-7) ) ) +transpose(((((X|((X+transpose(X,4) ) +transpose(X,7) ) ) |shuffle(X) ) +transpose(transpose(((arpeggio(X) +transpose(X,4) ) +transpose(shuffle(X) ,7) ) ,-5) ,4) ) +transpose(transpose(((X+transpose(X,4) ) +transpose(X,7) ) ,-7) ,7) ) ,4) ) +transpose(transpose(arpeggio(transpose(X,-5) ) ,4) ,7) ) ) ) ,12) ) ,4) ) +transpose(step(step(transpose(transpose(transpose(shuffle(arpeggio(X) ) ,4) ,-7) ,-7) ,12) ,12) ,7) ) +transpose(transpose((transpose(arpeggio((shuffle(transpose(X,-7) ) +X) ) ,4) +(echo((X+transpose(X,-5) ) ,4,6) |transpose(transpose((X+transpose(X,7) ) ,-5) ,-5) ) ) ,4) ,12) ) |(arpeggio((((arpeggio((((arpeggio((X+X) ) +(transpose(X,4) +transpose(X,-7) ) ) |(echo((X+transpose(X,12) ) ,4,6) |(X+transpose(X,7) ) ) ) +transpose(arpeggio(X) ,-7) ) ) +(echo(shuffle((X+transpose(X,7) ) ) ,4,6) +((step(((X+transpose(X,7) ) +transpose(shuffle(X) ,12) ) ,12) +transpose(transpose(X,-5) ,12) ) |transpose((X+shuffle(X) ) ,-7) ) ) ) +transpose(shuffle(transpose((arpeggio(shuffle(shuffle(X) ) ) +(transpose(X,4) +arpeggio(shuffle(step(X,12) ) ) ) ) ,-7) ) ,7) ) +transpose(shuffle(transpose(transpose(X,4) ,4) ) ,7) ) ) |shuffle((shuffle((transpose(((X+X) +transpose(X,12) ) ,4) |X) ) +transpose(echo(X,4,6) ,4) ) ) ) ) ,4) ) +transpose(arpeggio(((shuffle(transpose(((arpeggio((X+X) ) +transpose(echo(((X+transpose(X,4) ) +transpose(X,7) ) ,4,6) ,12) ) +((transpose(step(transpose(X,-7) ,12) ,-7) +transpose(transpose(arpeggio(X) ,4) ,4) ) +transpose((((X+transpose(X,7) ) +transpose((X|X) ,4) ) +transpose(X,7) ) ,7) ) ) ,-5) ) +transpose(transpose(transpose(transpose(echo(transpose(transpose(X,-7) ,-7) ,4,6) ,4) ,-5) ,-7) ,-7) ) +transpose(transpose(transpose(((transpose((step(X,12) +shuffle((X+(X+transpose(X,12) ) ) ) ) ,4) +transpose(step((shuffle(X) +transpose(transpose(X,-5) ,7) ) ,12) ,4) ) +transpose((echo(transpose(X,-7) ,4,6) |arpeggio(((X+transpose(X,4) ) +transpose(transpose(X,-5) ,7) ) ) ) ,7) ) ,-5) ,-7) ,-5) ) ) ,7) ) ,4) ) ) ,7) )
random seed used was 171444996

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