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 18 generations the expression "X" became this:
transpose((echo(((shuffle(((transpose(((transpose(step(X,12) ,-5) +transpose(X,4) ) +transpose((echo(X,4,6) +((X+transpose(X,12) ) |shuffle(X) ) ) ,7) ) ,4) |transpose(((X+X) +transpose(((X+transpose(arpeggio(X) ,4) ) +transpose(transpose(X,-5) ,7) ) ,7) ) ,-5) ) |(((transpose((X|X) ,-7) +transpose(shuffle(((X|X) +transpose(transpose(X,4) ,7) ) ) ,4) ) +transpose(step(X,12) ,7) ) +transpose(((transpose((X+transpose(X,12) ) ,-5) +transpose(echo((X+transpose(X,7) ) ,4,6) ,7) ) +arpeggio(X) ) ,7) ) ) ) +(((((((((shuffle(X) +transpose((X+transpose(X,7) ) ,4) ) +transpose(X,7) ) +transpose(((X+X) +X) ,4) ) +transpose((X+transpose(transpose(X,-5) ,7) ) ,4) ) |transpose(transpose(transpose(X,-5) ,-7) ,4) ) +transpose(step(echo(transpose(transpose(((X+transpose(transpose(X,-7) ,4) ) +transpose(X,7) ) ,-5) ,4) ,4,6) ,12) ,4) ) +transpose((step(transpose(transpose(transpose(X,-5) ,4) ,-7) ,12) +transpose((((transpose((X|(X+transpose(X,12) ) ) ,4) +transpose(transpose((X+transpose(((X+transpose(X,4) ) +transpose(X,7) ) ,7) ) ,-5) ,4) ) +transpose((transpose(X,-5) |X) ,7) ) +transpose((((X|step(X,12) ) +transpose(((((X+transpose(X,7) ) +transpose(transpose(X,4) ,12) ) +transpose(shuffle((X+transpose(X,7) ) ) ,12) ) +transpose(transpose(arpeggio(X) ,-5) ,12) ) ,4) ) +transpose(step(((X+transpose(transpose(X,-7) ,4) ) +transpose(transpose(X,4) ,7) ) ,12) ,7) ) ,12) ) ,7) ) ,7) ) +transpose((transpose(((X+transpose(((X+transpose(X,4) ) +transpose(X,7) ) ,4) ) +transpose(X,7) ) ,-7) +transpose((step(X,12) +transpose(arpeggio(step(X,12) ) ,7) ) ,12) ) ,4) ) +transpose((transpose(((X+transpose(((X+transpose(X,4) ) +transpose(X,7) ) ,7) ) +(((X+X) +transpose(transpose(X,4) ,12) ) +transpose((X+step(X,12) ) ,7) ) ) ,4) +arpeggio((((X+X) +echo(echo(X,4,6) ,4,6) ) |(X+transpose((transpose(X,-7) +(X+transpose(X,7) ) ) ,7) ) ) ) ) ,7) ) ) +transpose((transpose(echo(transpose(echo((((X|X) +transpose(transpose(echo((X|X) ,4,6) ,-7) ,7) ) |step((X|transpose(X,-5) ) ,12) ) ,4,6) ,-5) ,4,6) ,4) +echo((transpose(echo(shuffle(transpose(arpeggio(transpose(X,4) ) ,-5) ) ,4,6) ,-7) |transpose((((step(X,12) |transpose(X,4) ) +transpose(X,7) ) |transpose(shuffle(X) ,-7) ) ,-5) ) ,4,6) ) ,12) ) ,4,6) |transpose((step((arpeggio(arpeggio(arpeggio((step((transpose(X,4) |transpose(X,4) ) ,12) +transpose(transpose(arpeggio(shuffle(X) ) ,-7) ,7) ) ) ) ) +(echo(transpose(((step((((X+transpose(X,4) ) +transpose(X,7) ) |(X|X) ) ,12) +transpose(X,4) ) +transpose(step(X,12) ,4) ) ,-7) ,4,6) +transpose((transpose((shuffle((echo((X+transpose(X,7) ) ,4,6) |(X+transpose(transpose(X,4) ,7) ) ) ) +transpose(((X+X) |X) ,12) ) ,4) +transpose(arpeggio(((((X|X) +transpose(transpose(X,4) ,4) ) +transpose(step(X,12) ,7) ) +transpose((transpose(X,-7) +((X+transpose(X,4) ) +transpose(X,7) ) ) ,12) ) ) ,-7) ) ,7) ) ) ,12) +shuffle(transpose((arpeggio(shuffle(((X+(X|X) ) |transpose(transpose(X,4) ,4) ) ) ) |transpose(echo((transpose((X+X) ,4) +((X+transpose(X,12) ) |X) ) ,4,6) ,-5) ) ,4) ) ) ,4) ) ,4)
random seed used was 209388457 EXPR = (transpose(transpose(((transpose(echo((((transpose((((X+transpose(X,4) ) +transpose(X,7) ) +transpose(X,7) ) ,-7) +transpose((X+transpose(transpose(transpose(X,-7) ,-5) ,7) ) ,12) ) +transpose(transpose((transpose(transpose(X,4) ,-7) +transpose((step(X,12) +(X+transpose(X,12) ) ) ,7) ) ,-7) ,12) ) +transpose((((arpeggio(transpose((X+(X+X) ) ,4) ) |transpose(((echo(X,4,6) +transpose(X,7) ) |echo(shuffle((X+transpose(X,12) ) ) ,4,6) ) ,4) ) +transpose((transpose((echo(X,4,6) +arpeggio(X) ) ,4) |transpose((shuffle(arpeggio(X) ) +shuffle(X) ) ,-5) ) ,4) ) +transpose(transpose((transpose(X,-7) |(X+transpose(X,12) ) ) ,-5) ,7) ) ,-5) ) ,4,6) ,-5) +transpose(((step(step(shuffle((transpose(transpose((transpose(X,4) |(transpose(X,4) +transpose(X,-7) ) ) ,-7) ,4) +((X+transpose((X+transpose(X,12) ) ,12) ) |((X+transpose(X,4) ) +transpose(X,7) ) ) ) ) ,12) ,12) +transpose((transpose(shuffle(((transpose(arpeggio(X) ,-5) |arpeggio((X|X) ) ) +transpose((transpose(X,-7) +transpose(transpose(X,4) ,7) ) ,12) ) ) ,-7) |transpose(transpose(step((echo(X,4,6) +X) ,12) ,4) ,-5) ) ,7) ) +transpose(transpose(((transpose(((((X+transpose(X,7) ) +arpeggio(X) ) +transpose(X,12) ) |transpose(transpose(X,-5) ,-7) ) ,4) +transpose(arpeggio(transpose(echo(transpose(transpose(X,-5) ,-7) ,4,6) ,4) ) ,4) ) +transpose(((shuffle((shuffle(step(X,12) ) +transpose((echo(X,4,6) +transpose(step(X,12) ,7) ) ,7) ) ) +(((arpeggio(((X+transpose(X,7) ) +transpose(X,4) ) ) |transpose(((X+transpose((step(X,12) +echo(X,4,6) ) ,4) ) +transpose((X|(X+transpose(X,12) ) ) ,7) ) ,4) ) +transpose(((transpose(echo(X,4,6) ,-5) +transpose(transpose(X,4) ,4) ) +transpose((transpose(((X+transpose(X,4) ) +transpose(X,7) ) ,-5) +shuffle(transpose(X,-5) ) ) ,7) ) ,4) ) +transpose((transpose(X,4) |X) ,7) ) ) |echo(step(transpose(((shuffle(X) +transpose(transpose(X,4) ,4) ) +transpose(transpose(X,-7) ,7) ) ,-5) ,12) ,4,6) ) ,7) ) ,-7) ,12) ) ,4) ) +transpose((((transpose(((transpose(step(X,12) ,-5) |((((step(transpose(X,-7) ,12) |transpose(transpose(transpose(X,-7) ,4) ,4) ) +transpose(arpeggio(transpose(X,4) ) ,7) ) +transpose(transpose(transpose(transpose(echo(X,4,6) ,-7) ,4) ,-5) ,4) ) +transpose(transpose(((transpose((X+transpose(X,12) ) ,4) +transpose(X,7) ) |(((arpeggio(X) |X) +transpose((((X+transpose(X,4) ) +transpose(X,7) ) +transpose(transpose(X,4) ,7) ) ,4) ) +transpose(X,7) ) ) ,-7) ,7) ) ) +transpose((transpose(transpose(echo(shuffle((X|X) ) ,4,6) ,-5) ,4) |transpose((echo(step(arpeggio(X) ,12) ,4,6) +transpose(transpose(((X+transpose(X,7) ) +transpose(((X+transpose(X,7) ) +transpose(step(X,12) ,7) ) ,12) ) ,-5) ,12) ) ,-5) ) ,12) ) ,4) +transpose(transpose(X,-5) ,7) ) +transpose((transpose(transpose((arpeggio(transpose(X,-5) ) +transpose(transpose(X,-7) ,12) ) ,-7) ,-7) +(((transpose(transpose((X+X) ,-7) ,4) |shuffle((shuffle(((X+transpose(X,4) ) +transpose(X,7) ) ) +transpose(X,12) ) ) ) |shuffle(transpose(((((arpeggio(step(X,12) ) +transpose((X+X) ,4) ) +transpose((X+transpose(X,7) ) ,7) ) +transpose(transpose(X,-5) ,4) ) +transpose(transpose(transpose(X,-5) ,-5) ,7) ) ,-5) ) ) +transpose(shuffle(echo((arpeggio(X) +transpose(transpose(X,4) ,12) ) ,4,6) ) ,12) ) ) ,12) ) +echo(transpose(((transpose(((X+(X+transpose(X,12) ) ) +(X+X) ) ,4) +(transpose(transpose(X,4) ,4) +transpose(transpose(echo(X,4,6) ,-7) ,7) ) ) +transpose(arpeggio(echo(((X+X) +transpose(echo(X,4,6) ,-7) ) ,4,6) ) ,7) ) ,-7) ,4,6) ) ,7) ) ,-7) ,4) +transpose(((((((step(shuffle(echo(transpose(X,-5) ,4,6) ) ,12) +transpose((((((X|X) |transpose((((X+transpose(X,7) ) +(X+transpose(transpose(X,-5) ,7) ) ) +arpeggio(shuffle(X) ) ) ,-5) ) +((((X+X) +transpose((X|X) ,7) ) +transpose(X,4) ) +transpose(arpeggio(X) ,7) ) ) +transpose(((transpose(echo(transpose(X,-5) ,4,6) ,4) +transpose((((((X+transpose(X,12) ) +transpose(transpose(X,-7) ,7) ) +transpose((shuffle((((X+transpose(X,4) ) +transpose(X,7) ) +X) ) |X) ,4) ) +transpose(transpose(step((arpeggio(X) +X) ,12) ,-5) ,7) ) +arpeggio(echo((transpose(X,-7) +transpose((X+transpose(X,7) ) ,12) ) ,4,6) ) ) ,4) ) +transpose(echo(transpose(X,4) ,4,6) ,7) ) ,4) ) +transpose((((((((X+transpose(X,4) ) +transpose(X,7) ) +transpose(arpeggio(step(X,12) ) ,4) ) +transpose(((transpose(X,-5) +transpose((X+X) ,4) ) +transpose(((X+transpose(X,4) ) +transpose(X,7) ) ,7) ) ,7) ) |(transpose((X+transpose(X,12) ) ,-7) +transpose((transpose(transpose(X,-7) ,-7) +transpose((X+X) ,12) ) ,7) ) ) |transpose(transpose(((X+transpose(step(X,12) ,4) ) +transpose(X,7) ) ,4) ,-5) ) +transpose(transpose((transpose(transpose(X,-7) ,-5) +transpose((X+X) ,-5) ) ,-5) ,12) ) ,7) ) ,4) ) +transpose(transpose(transpose(X,4) ,-7) ,7) ) +transpose(((echo((step(((transpose(X,-5) +transpose(X,4) ) +transpose(arpeggio(X) ,7) ) ,12) |(step(((X+X) +(X+X) ) ,12) |((X+transpose((X+X) ,4) ) +transpose(transpose(X,4) ,7) ) ) ) ,4,6) +transpose(transpose((transpose((transpose(X,4) +transpose(transpose(X,-5) ,7) ) ,4) |((((X+(X+X) ) +transpose(X,7) ) +transpose((shuffle(((X+X) +(X|X) ) ) +transpose(((X|X) |transpose(X,4) ) ,7) ) ,4) ) +transpose(transpose(transpose(echo(X,4,6) ,4) ,-7) ,7) ) ) ,-5) ,4) ) +transpose(transpose((echo(((shuffle((transpose(arpeggio(X) ,4) +transpose(shuffle(transpose(X,4) ) ,7) ) ) +transpose((transpose(transpose((X|X) ,-7) ,4) +transpose(transpose((X+transpose(X,7) ) ,4) ,7) ) ,4) ) +transpose(step((transpose(echo(X,4,6) ,4) +transpose(arpeggio(X) ,7) ) ,12) ,7) ) ,4,6) |transpose(((transpose(transpose(echo(arpeggio(X) ,4,6) ,-7) ,-7) +transpose(step(X,12) ,7) ) +transpose((X+transpose(arpeggio(((X+transpose(X,4) ) +transpose(X,7) ) ) ,7) ) ,7) ) ,-7) ) ,-7) ,7) ) ,4) ) +transpose(transpose(((transpose(transpose(echo(X,4,6) ,-5) ,-5) |(shuffle(transpose((transpose(X,-7) +transpose(transpose(X,4) ,12) ) ,4) ) +transpose((transpose(((transpose((X+X) ,4) +transpose(transpose((X|X) ,-7) ,4) ) +transpose((X+X) ,7) ) ,4) +((X+transpose(X,7) ) +transpose(arpeggio(transpose((X+X) ,4) ) ,7) ) ) ,7) ) ) +transpose(transpose(transpose(transpose(((X+transpose(X,4) ) +transpose(X,7) ) ,4) ,-7) ,-5) ,7) ) ,-5) ,7) ) +transpose(arpeggio((transpose(transpose(shuffle(X) ,-5) ,-7) |((X+transpose(X,12) ) +(X+transpose(X,7) ) ) ) ) ,12) ) |transpose(arpeggio((transpose(((step(X,12) +transpose(echo(X,4,6) ,4) ) +transpose(step(arpeggio(X) ,12) ,7) ) ,-5) |(((((step(X,12) +transpose(((step(X,12) +transpose(((X+transpose(X,4) ) +transpose(arpeggio(X) ,7) ) ,4) ) +transpose((X+transpose(X,7) ) ,7) ) ,4) ) +transpose(((X+transpose((((X+transpose(X,12) ) +transpose(arpeggio(X) ,4) ) +transpose(X,7) ) ,4) ) +transpose((echo(X,4,6) |X) ,7) ) ,7) ) +((transpose(arpeggio(X) ,4) +(X+transpose((X|X) ,7) ) ) +transpose(transpose(((X|transpose(X,-5) ) +(X|X) ) ,4) ,12) ) ) +transpose(step(step((transpose((X|X) ,-5) +transpose(X,-5) ) ,12) ,12) ,7) ) |((echo((shuffle(transpose(X,-7) ) |((shuffle(transpose(X,-5) ) +transpose((step((X+transpose(X,7) ) ,12) +(X+X) ) ,4) ) +transpose(echo(transpose((X|X) ,-7) ,4,6) ,7) ) ) ,4,6) +transpose((step(X,12) +(((X+transpose((X|X) ,12) ) +arpeggio((X+transpose(X,12) ) ) ) +transpose((transpose(X,-7) +shuffle(X) ) ,7) ) ) ,4) ) +transpose(transpose(transpose(transpose(transpose((X|X) ,-5) ,4) ,4) ,-7) ,7) ) ) ) ) ,-5) ) ,-5) )
random seed used was 0 EXPR = transpose(((((((transpose(shuffle(transpose((((((X|X) +transpose((X+transpose(X,12) ) ,4) ) +transpose(echo(X,4,6) ,7) ) +transpose(transpose(transpose((transpose(X,-5) +step(X,12) ) ,-7) ,4) ,4) ) +transpose((arpeggio(transpose(X,-5) ) +transpose(arpeggio(X) ,7) ) ,7) ) ,-7) ) ,-7) +transpose((((transpose((transpose(X,-7) +transpose(echo(X,4,6) ,7) ) ,-7) |step(transpose(X,-5) ,12) ) +transpose((transpose(transpose(transpose(X,-5) ,-7) ,4) +echo(((transpose(X,-5) +arpeggio(X) ) +transpose(step(X,12) ,7) ) ,4,6) ) ,4) ) +transpose(((echo(echo(X,4,6) ,4,6) |arpeggio((transpose(X,-7) +((X|X) +transpose(X,7) ) ) ) ) +transpose((((transpose(transpose(X,-5) ,-5) +transpose(transpose(transpose(X,4) ,-7) ,4) ) +transpose(arpeggio(X) ,7) ) |step((X+transpose(X,12) ) ,12) ) ,7) ) ,7) ) ,4) ) +transpose((echo(((step(X,12) +(transpose(transpose(X,4) ,4) |transpose(X,-7) ) ) +transpose((((((X+transpose(shuffle(X) ,4) ) +transpose(X,7) ) +transpose((X+X) ,7) ) |shuffle((((X+X) +transpose((X+X) ,4) ) +transpose(echo(X,4,6) ,7) ) ) ) +transpose(shuffle(transpose(transpose(X,-5) ,-7) ) ,7) ) ,12) ) ,4,6) +transpose(((transpose(arpeggio(transpose(X,-5) ) ,-7) +transpose((step(transpose(X,4) ,12) +transpose((transpose(X,-7) |echo(transpose(step(X,12) ,-7) ,4,6) ) ,7) ) ,4) ) +transpose(((step(X,12) +X) +transpose((X|X) ,12) ) ,7) ) ,12) ) ,7) ) +transpose(transpose((((((((X|X) +transpose(arpeggio(echo(X,4,6) ) ,12) ) +transpose((transpose(transpose(X,-7) ,4) |X) ,12) ) +arpeggio((X|X) ) ) +transpose((step((transpose((X|X) ,4) +transpose(X,-7) ) ,12) +echo((transpose(X,-5) |(transpose(X,-5) +step(X,12) ) ) ,4,6) ) ,4) ) +transpose((X+transpose(transpose(transpose(X,4) ,4) ,12) ) ,7) ) +transpose(step(transpose(((X+transpose(X,4) ) +transpose(((X+transpose(X,4) ) +transpose(X,7) ) ,7) ) ,-7) ,12) ,7) ) ,-7) ,12) ) +transpose(((shuffle(step(transpose(echo(((transpose(((step(X,12) +transpose((X+X) ,4) ) +transpose(X,7) ) ,-7) +transpose(transpose(((arpeggio(echo(X,4,6) ) +transpose(transpose(shuffle(X) ,-7) ,4) ) +transpose(shuffle((X+transpose(X,7) ) ) ,7) ) ,-7) ,4) ) +transpose(transpose(((X+X) +transpose((X|X) ,12) ) ,4) ,7) ) ,4,6) ,4) ,12) ) +transpose(transpose(((arpeggio((shuffle(transpose(transpose(X,-7) ,-7) ) +(((((X+transpose(X,4) ) +transpose(X,7) ) +(transpose(X,-5) |(X|X) ) ) +transpose(X,-5) ) +(transpose(shuffle(transpose(X,4) ) ,-7) +transpose(transpose((((X+transpose(X,4) ) +transpose(X,7) ) |(X+X) ) ,-7) ,7) ) ) ) ) |transpose(transpose(transpose(step(((((X+transpose(X,4) ) +transpose(X,7) ) +transpose(shuffle(X) ,7) ) |transpose(transpose(((X+transpose(X,4) ) +transpose(X,7) ) ,-5) ,-5) ) ,12) ,4) ,-5) ,-5) ) +(((transpose((((X|X) +transpose(X,4) ) +transpose((X|X) ,7) ) ,4) |transpose(((transpose((arpeggio(X) +transpose(((X|X) +transpose(transpose(X,-7) ,7) ) ,12) ) ,-7) |transpose(((transpose(X,4) +transpose(transpose(X,-5) ,4) ) +transpose((X+X) ,7) ) ,4) ) +transpose(transpose(echo((X+transpose(X,12) ) ,4,6) ,-7) ,12) ) ,4) ) +step(((arpeggio(((shuffle(step(X,12) ) +(X|X) ) +(transpose(X,-7) +(X+transpose(X,-7) ) ) ) ) |arpeggio(transpose(((arpeggio(X) |X) +transpose((transpose(X,-7) +transpose(transpose(X,-7) ,12) ) ,12) ) ,-5) ) ) +transpose((((transpose((X+transpose((X+transpose(X,-7) ) ,12) ) ,-7) +transpose(transpose((X+X) ,4) ,4) ) +transpose(shuffle(transpose(X,4) ) ,7) ) +transpose(((X+(X+transpose(X,12) ) ) |shuffle(transpose(transpose(X,4) ,4) ) ) ,12) ) ,12) ) ,12) ) +transpose(transpose(transpose(transpose(transpose(((X+((X+transpose(X,4) ) +transpose(X,7) ) ) +(((X+transpose(((X+transpose(X,4) ) +transpose(X,7) ) ,4) ) +transpose(shuffle(X) ,7) ) +transpose(X,12) ) ) ,4) ,4) ,4) ,-5) ,7) ) ) ,-5) ,4) ) +transpose(((transpose(step((((arpeggio((X|X) ) +transpose(shuffle((arpeggio(X) |(X+X) ) ) ,4) ) +transpose(((shuffle(X) +transpose(transpose(X,-7) ,4) ) +transpose(transpose(X,-7) ,7) ) ,7) ) |transpose(X,4) ) ,12) ,-7) +transpose(((echo(transpose(shuffle((transpose(((transpose(X,4) +transpose(X,4) ) +transpose((((X+transpose(X,4) ) +transpose(X,7) ) |X) ,7) ) ,-5) +arpeggio(transpose((X+X) ,-5) ) ) ) ,-7) ,4,6) +transpose(transpose(((X+transpose(X,4) ) +transpose(transpose(X,-7) ,7) ) ,-5) ,12) ) +(step(X,12) |transpose(transpose(X,-7) ,-7) ) ) ,7) ) |transpose(transpose(shuffle(step((transpose(echo(X,4,6) ,-7) +step((X+arpeggio(X) ) ,12) ) ,12) ) ,4) ,-7) ) ,7) ) ,12) ) +transpose((transpose(((transpose(transpose(((transpose(X,-7) |(X|X) ) |(((X+transpose(X,12) ) +transpose(echo((X+transpose(X,12) ) ,4,6) ,4) ) +transpose((transpose(X,-5) |(X|X) ) ,7) ) ) ,-7) ,-5) |(transpose(((((X+X) +((X+transpose(X,4) ) +transpose(X,7) ) ) |transpose(transpose(X,-7) ,-7) ) +transpose((((echo((X+X) ,4,6) +(transpose(X,-7) +transpose(echo(X,4,6) ,12) ) ) +transpose(shuffle(transpose(X,4) ) ,4) ) +transpose(transpose(((X+transpose(X,7) ) +transpose(((transpose(X,4) +transpose(shuffle(X) ,4) ) +transpose(X,7) ) ,12) ) ,4) ,7) ) ,7) ) ,4) +transpose(((((X+transpose((X+X) ,4) ) +transpose(X,7) ) +X) +transpose((X+transpose(((X+transpose(X,4) ) +transpose(X,7) ) ,7) ) ,-5) ) ,7) ) ) +transpose((transpose(shuffle(transpose(((((arpeggio(X) +transpose(X,4) ) +transpose(X,7) ) |echo(X,4,6) ) +((transpose(X,4) +transpose(X,4) ) +transpose((X|X) ,7) ) ) ,-7) ) ,4) +transpose(arpeggio(((transpose((X+X) ,-7) +transpose(transpose(X,-5) ,4) ) +transpose(((X+transpose((X|X) ,12) ) |arpeggio(echo(X,4,6) ) ) ,7) ) ) ,7) ) ,12) ) ,-7) |(arpeggio(arpeggio((echo(shuffle(X) ,4,6) +transpose(echo(transpose(X,4) ,4,6) ,-7) ) ) ) +transpose(echo(transpose(echo(transpose(arpeggio(X) ,-7) ,4,6) ,4) ,4,6) ,4) ) ) ,4) ) +transpose((transpose((((step(transpose((transpose(X,-5) +transpose(step(step(transpose(X,-5) ,12) ,12) ,12) ) ,-5) ,12) +transpose(((((transpose(transpose(step(step(X,12) ,12) ,-7) ,-7) +transpose(transpose(transpose(X,-5) ,4) ,4) ) +transpose(transpose(((step(X,12) +((X+transpose(X,4) ) +transpose(X,7) ) ) +transpose((echo(X,4,6) +transpose((X+X) ,7) ) ,7) ) ,4) ,7) ) +(arpeggio(transpose(transpose((((X+X) +transpose(X,4) ) +transpose(((X+transpose(X,4) ) +transpose(X,7) ) ,7) ) ,-7) ,-7) ) +step(step(X,12) ,12) ) ) |transpose((X+step((step((X|X) ,12) |X) ,12) ) ,4) ) ,4) ) +transpose(((transpose(transpose(shuffle(transpose(shuffle(X) ,4) ) ,-5) ,4) +(step((transpose((X+(X|X) ) ,4) +transpose((arpeggio(X) +transpose(transpose(arpeggio(X) ,-7) ,12) ) ,7) ) ,12) |transpose(transpose(((step(step(X,12) ,12) +transpose(((X+transpose(X,12) ) +transpose(X,7) ) ,4) ) +transpose(transpose((X+transpose(X,7) ) ,-5) ,7) ) ,4) ,-5) ) ) +transpose(arpeggio(transpose(transpose(shuffle(X) ,4) ,4) ) ,7) ) ,7) ) +(transpose(shuffle((transpose(transpose(X,-5) ,-7) +transpose(transpose((((X|X) +transpose((X+transpose(X,7) ) ,12) ) +(X+transpose((X+transpose(X,12) ) ,12) ) ) ,-5) ,7) ) ) ,-5) +(transpose(transpose(transpose(shuffle((X+transpose(X,12) ) ) ,-5) ,-5) ,-7) +transpose((transpose((((transpose(X,-5) +transpose(((X+transpose(X,12) ) +transpose((X|X) ,12) ) ,12) ) +transpose(step((X+X) ,12) ,-7) ) +transpose(((arpeggio(X) +(arpeggio(((X+transpose(X,4) ) +transpose(X,7) ) ) +transpose(((X+transpose((X+X) ,4) ) +transpose((X+transpose(X,7) ) ,7) ) ,7) ) ) +echo((transpose(X,-5) +X) ,4,6) ) ,12) ) ,-5) +transpose(arpeggio((((echo(X,4,6) +transpose(X,4) ) +transpose(X,7) ) |transpose(transpose(X,-5) ,-5) ) ) ,12) ) ,7) ) ) ) ,-5) |transpose(transpose(transpose((((step((transpose(transpose(transpose((echo(X,4,6) +transpose(echo(X,4,6) ,12) ) ,4) ,4) ,4) +transpose((transpose(transpose((X+transpose(X,12) ) ,-5) ,4) +shuffle(transpose(arpeggio(X) ,-7) ) ) ,7) ) ,12) +transpose((transpose(transpose(transpose((X|X) ,-5) ,-7) ,-5) |echo(transpose(transpose(X,4) ,4) ,4,6) ) ,7) ) +transpose(transpose(transpose(transpose(transpose(transpose(echo(X,4,6) ,-5) ,-7) ,-5) ,-5) ,-5) ,4) ) +transpose(echo(arpeggio((arpeggio(step(X,12) ) +transpose(echo((X+(X+X) ) ,4,6) ,12) ) ) ,4,6) ,7) ) ,4) ,-7) ,-5) ) ,7) ) ,-7)
random seed used was 0 EXPR = transpose(transpose((echo(shuffle(((transpose((((echo(echo(transpose((X+transpose(X,12) ) ,-5) ,4,6) ,4,6) +transpose(transpose(transpose((X+transpose(X,12) ) ,4) ,4) ,12) ) +transpose((transpose(((X+X) +(X+transpose(X,12) ) ) ,-7) +arpeggio(transpose((shuffle(X) +transpose(X,7) ) ,4) ) ) ,4) ) +transpose((transpose((transpose(transpose(X,4) ,4) |(transpose(X,-7) +(X+transpose(X,7) ) ) ) ,-5) |transpose((X+transpose(X,12) ) ,-7) ) ,7) ) ,-7) +transpose((step(transpose(((echo(X,4,6) +transpose(shuffle(X) ,12) ) +transpose(((X+transpose(X,7) ) +transpose((X+X) ,7) ) ,12) ) ,4) ,12) +(((X+transpose(transpose(X,-5) ,4) ) +transpose((X|X) ,7) ) +transpose((X+X) ,-7) ) ) ,4) ) +transpose(((echo(echo(shuffle((((step(X,12) +transpose(transpose(X,-7) ,7) ) +transpose((X+transpose((X+X) ,12) ) ,4) ) +transpose((X|(X|X) ) ,7) ) ) ,4,6) ,4,6) +transpose((((transpose(transpose((X+transpose((X|X) ,12) ) ,-7) ,4) +(echo(transpose(transpose(X,4) ,-5) ,4,6) |((X+transpose(X,4) ) +transpose(transpose(X,-5) ,7) ) ) ) +transpose((transpose(X,-5) |X) ,12) ) +transpose(((transpose(transpose((X+transpose(X,12) ) ,-7) ,-5) +transpose((transpose(((X+transpose(X,7) ) +transpose(X,12) ) ,4) +transpose(transpose(echo(X,4,6) ,4) ,12) ) ,7) ) |shuffle(((((X+transpose((X|X) ,12) ) +transpose(transpose(transpose(X,-5) ,-5) ,7) ) +X) |transpose((transpose(X,-7) +transpose(transpose(X,4) ,7) ) ,4) ) ) ) ,7) ) ,4) ) +transpose(transpose(shuffle(((transpose(step(X,12) ,4) +transpose(((X+X) |shuffle(X) ) ,4) ) +transpose(((X+X) +(X+(X|X) ) ) ,7) ) ) ,-7) ,7) ) ,7) ) ) ,4,6) +transpose(arpeggio(shuffle(shuffle(arpeggio(step((((X|shuffle(X) ) +transpose(step(shuffle((X+transpose(X,7) ) ) ,12) ,4) ) +transpose(((arpeggio(X) +transpose(step(X,12) ,4) ) +transpose((X+transpose((X+transpose(X,7) ) ,12) ) ,7) ) ,7) ) ,12) ) ) ) ) ,7) ) ,-7) ,-7)
random seed used was 0

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