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 15 generations the expression "X" became this:
transpose(echo(transpose(transpose(((transpose((transpose(echo(transpose(((step(echo(X,4,6) ,12) +transpose(((X+transpose((X+X) ,4) ) +transpose(X,7) ) ,4) ) +transpose(transpose(X,4) ,7) ) ,4) ,4,6) ,-7) +transpose(((transpose(((((X+transpose(X,12) ) +transpose(X,4) ) +transpose(X,7) ) +transpose(echo(X,4,6) ,7) ) ,4) +transpose((((X+transpose(X,12) ) +transpose(transpose(X,-5) ,7) ) +transpose((transpose(X,4) |(((X+transpose(X,4) ) +transpose(X,7) ) +X) ) ,-5) ) ,4) ) +transpose((echo((X+X) ,4,6) |((X+transpose(shuffle(X) ,7) ) |arpeggio((X+transpose(X,7) ) ) ) ) ,7) ) ,7) ) ,-7) +transpose(transpose((shuffle((shuffle(transpose(X,-5) ) |step(step(X,12) ,12) ) ) +((((((transpose(X,-7) +transpose(X,4) ) +transpose(transpose(X,4) ,7) ) +transpose(((X|X) |(X|X) ) ,12) ) +((X+transpose(X,7) ) +transpose((echo(X,4,6) |X) ,12) ) ) |echo(arpeggio(shuffle(X) ) ,4,6) ) |((arpeggio((X+shuffle(X) ) ) +transpose(step(arpeggio(((shuffle(X) +transpose((X+transpose(X,7) ) ,4) ) +transpose(arpeggio(X) ,7) ) ) ,12) ,4) ) +transpose(step(shuffle(X) ,12) ,7) ) ) ) ,4) ,7) ) |transpose(((echo(step(transpose((X+transpose(X,7) ) ,-5) ,12) ,4,6) |transpose((X+transpose(X,12) ) ,4) ) |transpose(shuffle(transpose((transpose(X,-7) +X) ,-7) ) ,4) ) ,-7) ) ,-5) ,-7) ,4,6) ,4)
random seed used was 10201 EXPR = arpeggio((((arpeggio(shuffle((((((step(transpose(X,4) ,12) +transpose(X,4) ) +transpose((arpeggio((X+transpose(X,12) ) ) +transpose(shuffle(echo(X,4,6) ) ,7) ) ,4) ) +transpose(transpose(X,-7) ,7) ) +step((X+transpose(transpose(X,4) ,12) ) ,12) ) |(((((transpose(X,-7) +transpose(X,12) ) +transpose((transpose(transpose(shuffle((X+(X|X) ) ) ,-7) ,-5) +transpose(((X+transpose(X,7) ) +(X|(X|X) ) ) ,7) ) ,4) ) +transpose(echo(((((transpose(X,4) +transpose(X,4) ) +transpose(X,7) ) +(transpose(X,-7) |X) ) |((((X+transpose(X,4) ) +transpose(X,7) ) +transpose(((X+transpose(shuffle(X) ,4) ) +transpose(step(X,12) ,7) ) ,4) ) +transpose(echo(transpose(X,4) ,4,6) ,7) ) ) ,4,6) ,7) ) +transpose((transpose(transpose(((X+X) +((X+transpose(X,4) ) +transpose(X,7) ) ) ,-5) ,4) |((X+transpose((X+transpose(X,7) ) ,4) ) +transpose((X+transpose(X,7) ) ,7) ) ) ,4) ) +transpose(((transpose(X,-5) |transpose((((X+transpose(X,4) ) +transpose(X,7) ) +(X|X) ) ,-5) ) |((((((X|X) |(X+transpose(X,7) ) ) +transpose(transpose(((X+transpose(X,4) ) +transpose(X,7) ) ,-7) ,4) ) +transpose(X,7) ) +transpose(transpose(X,-5) ,4) ) +transpose(((X+X) +(shuffle(X) +X) ) ,7) ) ) ,7) ) ) ) ) +transpose(transpose(((((transpose(arpeggio((transpose(X,-5) |(X|X) ) ) ,-7) +((transpose(((X+transpose(X,12) ) |transpose(X,4) ) ,-5) +X) +transpose(transpose(arpeggio(transpose((X+transpose(X,12) ) ,-7) ) ,-5) ,7) ) ) +transpose(((transpose((((shuffle(X) |((X+transpose(X,4) ) +transpose(X,7) ) ) +(echo(X,4,6) +step(X,12) ) ) +shuffle(transpose(X,4) ) ) ,-7) |((transpose(transpose(X,4) ,-5) +transpose(echo(X,4,6) ,4) ) +transpose(echo((X|X) ,4,6) ,7) ) ) |transpose(transpose(transpose(X,-7) ,-7) ,4) ) ,4) ) +transpose(transpose(transpose((transpose(transpose(transpose(X,-7) ,4) ,-5) +(((shuffle(X) +echo(X,4,6) ) +transpose((echo(transpose(X,4) ,4,6) +transpose(X,-7) ) ,4) ) +transpose(((transpose(X,-5) +transpose(((X+transpose(X,4) ) +transpose(X,7) ) ,4) ) +transpose(((X|X) +transpose(X,12) ) ,7) ) ,7) ) ) ,-5) ,-5) ,7) ) +transpose(echo(echo(shuffle(shuffle((transpose((X+transpose(X,7) ) ,-7) +transpose(X,7) ) ) ) ,4,6) ,4,6) ,4) ) ,4) ,4) ) +transpose(((transpose(echo(((transpose(((arpeggio((X+transpose(transpose(X,4) ,12) ) ) +transpose(transpose(transpose(X,4) ,-7) ,4) ) +transpose(transpose(X,-7) ,7) ) ,-5) +transpose((transpose(X,-7) +transpose((X+X) ,12) ) ,4) ) +transpose(((((arpeggio(X) +transpose((X+X) ,7) ) +X) +transpose(transpose(echo(X,4,6) ,-5) ,12) ) +(transpose(X,-7) +transpose(((X+transpose(X,4) ) |shuffle(transpose(X,-5) ) ) ,12) ) ) ,7) ) ,4,6) ,4) +transpose(((transpose((transpose(echo(transpose((X+transpose(X,12) ) ,4) ,4,6) ,-7) +transpose((step((X+X) ,12) |((transpose(X,-7) +((X+transpose(X,4) ) +transpose(X,7) ) ) +transpose(shuffle((X+X) ) ,12) ) ) ,7) ) ,-7) +transpose(transpose(shuffle(X) ,-7) ,4) ) +transpose((((((transpose(X,4) +transpose(transpose(X,4) ,7) ) +transpose(transpose(transpose(X,-7) ,4) ,4) ) +transpose(step(echo(X,4,6) ,12) ,7) ) +((((X+transpose(X,4) ) +transpose(X,7) ) +transpose((X+transpose(X,7) ) ,12) ) +transpose((transpose(X,4) |(X|X) ) ,12) ) ) +transpose(transpose(((X+transpose(X,4) ) +transpose(X,7) ) ,-7) ,7) ) ,7) ) ,4) ) +transpose(transpose(transpose((transpose(((X+X) +((X+transpose(X,7) ) +transpose(X,4) ) ) ,-5) |((transpose(X,-7) +transpose(echo(((X|X) +X) ,4,6) ,4) ) +transpose(transpose((X+X) ,4) ,7) ) ) ,-7) ,-5) ,7) ) ,7) ) |(((arpeggio(step(((((arpeggio(step(arpeggio(X) ,12) ) |transpose(X,-5) ) |arpeggio((X+transpose(X,7) ) ) ) +transpose(transpose((transpose(transpose(X,-7) ,4) +(((X+X) +transpose(X,4) ) +transpose((X|X) ,7) ) ) ,4) ,7) ) +(shuffle(((X+transpose(X,4) ) +transpose(X,7) ) ) +transpose(X,7) ) ) ,12) ) |transpose(((shuffle(transpose(transpose(((transpose(X,4) |arpeggio(X) ) |(transpose(X,-5) +transpose(X,7) ) ) ,4) ,4) ) +transpose(transpose((transpose(transpose((transpose(X,-7) +(X+transpose(X,12) ) ) ,-5) ,-7) +transpose(shuffle(((X+transpose(X,4) ) +transpose(X,7) ) ) ,7) ) ,-5) ,7) ) +transpose(shuffle(transpose(X,4) ) ,7) ) ,-7) ) +transpose(transpose(transpose(((echo((transpose(X,-7) +transpose((X+transpose(X,7) ) ,-7) ) ,4,6) +transpose(((transpose((transpose((X+X) ,4) |(X+(X+transpose(X,12) ) ) ) ,-5) +transpose((((X+transpose(X,4) ) +transpose(X,7) ) +transpose(X,12) ) ,-5) ) |echo(transpose(X,4) ,4,6) ) ,4) ) +transpose(((transpose(transpose(arpeggio(X) ,4) ,-7) +transpose(X,-7) ) +transpose((transpose(echo((X+transpose((X+X) ,4) ) ,4,6) ,4) +transpose(echo(((X+transpose((X+transpose(X,12) ) ,7) ) |echo(X,4,6) ) ,4,6) ,7) ) ,12) ) ,7) ) ,-7) ,-7) ,12) ) +transpose(transpose(((transpose(transpose((transpose((((X+transpose(X,4) ) +transpose(X,7) ) +transpose(transpose(X,4) ,7) ) ,-5) |(transpose((X+transpose(X,7) ) ,-5) +transpose(transpose(X,4) ,-7) ) ) ,4) ,-7) +transpose(echo(transpose((((((transpose(X,-7) |((X+transpose(X,7) ) +transpose(((X+transpose(X,4) ) +transpose(X,7) ) ,7) ) ) +transpose(transpose((echo(X,4,6) +transpose(X,-5) ) ,4) ,4) ) +transpose(arpeggio(step((X+X) ,12) ) ,7) ) +transpose(((X+X) +((X+X) +transpose((X+transpose(X,12) ) ,12) ) ) ,4) ) +transpose(step((X+(X|X) ) ,12) ,7) ) ,4) ,4,6) ,12) ) +transpose(((shuffle((((X+transpose(X,7) ) +transpose((X+X) ,7) ) +transpose(X,12) ) ) |transpose((X+transpose((((X+transpose(X,4) ) +transpose(X,7) ) |X) ,12) ) ,4) ) |transpose(transpose((((transpose(arpeggio(X) ,-5) +transpose(transpose((X+transpose(X,12) ) ,4) ,4) ) +transpose(X,7) ) +transpose((transpose(transpose(transpose(X,-5) ,-5) ,-5) |(transpose((X+X) ,-7) |shuffle((X+transpose(X,12) ) ) ) ) ,7) ) ,-5) ,-7) ) ,-5) ) ,4) ,7) ) ) )
random seed used was 0 EXPR = (step(shuffle((echo((arpeggio(transpose(X,-5) ) |transpose((X|X) ,4) ) ,4,6) |((transpose(echo(X,4,6) ,-5) +shuffle(((X+transpose(X,4) ) +transpose(X,7) ) ) ) |shuffle(((X|X) +transpose(((X|X) +transpose(X,7) ) ,12) ) ) ) ) ) ,12) +(shuffle(transpose(transpose(transpose(transpose(arpeggio(((arpeggio(X) +transpose(echo(X,4,6) ,4) ) +transpose((X+transpose(X,12) ) ,7) ) ) ,-5) ,-5) ,4) ,-5) ) +transpose(shuffle(((((arpeggio((arpeggio(step(X,12) ) |transpose((X+transpose(X,7) ) ,-5) ) ) +transpose((echo(X,4,6) +transpose(transpose(echo(((((X+transpose(X,4) ) +transpose(X,7) ) +transpose(X,4) ) +transpose(X,7) ) ,4,6) ,-5) ,12) ) ,12) ) |transpose(echo((((arpeggio(X) +transpose(X,12) ) +transpose(arpeggio(transpose(X,-5) ) ,12) ) +(transpose((X+transpose(X,7) ) ,4) +transpose((shuffle(transpose(X,4) ) +(X+echo(X,4,6) ) ) ,12) ) ) ,4,6) ,4) ) +transpose((transpose(transpose((echo(step((transpose(transpose(X,-7) ,-5) |(X+transpose(X,12) ) ) ,12) ,4,6) |(transpose(X,-5) +transpose((shuffle((X+transpose(X,12) ) ) +X) ,-7) ) ) ,-5) ,4) +transpose((((((X+X) |(X+arpeggio(X) ) ) +transpose(transpose(transpose(transpose(X,-7) ,-7) ,-7) ,4) ) +transpose(echo((((X+transpose(X,4) ) +transpose(X,7) ) |X) ,4,6) ,7) ) |transpose(echo(((((X+transpose(X,7) ) +arpeggio(X) ) +echo(X,4,6) ) +transpose(transpose(shuffle(X) ,4) ,4) ) ,4,6) ,4) ) ,7) ) ,4) ) +transpose((transpose(arpeggio(shuffle((((arpeggio(X) +transpose(X,12) ) +transpose(transpose((X+X) ,4) ,7) ) +(X|X) ) ) ) ,4) |step(step(echo(transpose((transpose(((X+transpose(X,12) ) |(X|X) ) ,4) +shuffle(X) ) ,-7) ,4,6) ,12) ,12) ) ,7) ) ) ,7) ) )
random seed used was 0 EXPR = transpose((shuffle((arpeggio(echo((arpeggio(transpose(((X|X) +X) ,-7) ) +transpose(transpose((((X|X) |shuffle(X) ) |transpose(X,4) ) ,4) ,7) ) ,4,6) ) +(transpose(transpose(transpose(X,-5) ,4) ,-5) +transpose((shuffle((echo(step((((X+X) +transpose((X+transpose(X,7) ) ,4) ) +transpose(step(X,12) ,7) ) ,12) ,4,6) +transpose(transpose(((((X+transpose(X,4) ) +transpose(X,7) ) +transpose(transpose(X,4) ,4) ) +transpose((X+X) ,7) ) ,-5) ,-5) ) ) +step(((((X+X) +transpose(((X+X) +transpose(transpose(arpeggio(X) ,-7) ,12) ) ,7) ) +transpose(transpose((transpose((X+transpose(X,7) ) ,-5) +transpose(X,7) ) ,-7) ,4) ) +transpose(step((step(X,12) +transpose((X+transpose(X,12) ) ,12) ) ,12) ,7) ) ,12) ) ,7) ) ) ) +transpose(((transpose(transpose(transpose((X+X) ,-5) ,-5) ,4) +transpose((transpose(transpose(transpose((transpose(X,-5) |shuffle(X) ) ,4) ,-7) ,-7) |echo(echo(X,4,6) ,4,6) ) ,4) ) +transpose((echo(transpose((transpose(X,-5) +transpose(((X+X) +shuffle(X) ) ,7) ) ,-7) ,4,6) |transpose(((transpose(arpeggio(X) ,4) +transpose((X+X) ,4) ) +transpose(transpose(transpose((X+transpose(X,7) ) ,-5) ,-7) ,7) ) ,-5) ) ,7) ) ,7) ) ,4)
random seed used was 0

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