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:
Seed:
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Generations:
Phrase for X:
# of Tracks:
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After 20 generations the expression "X" became this:
(shuffle(((transpose(shuffle((((transpose(((arpeggio((transpose((((arpeggio(transpose((X+transpose((X+transpose(X,12) ) ,7) ) ,-7) ) +transpose(echo(transpose(transpose((X|X) ,-7) ,-5) ,4,6) ,4) ) +transpose(step(((step(X,12) +transpose((X|X) ,4) ) +transpose(X,7) ) ,12) ,7) ) |(((transpose(X,-5) +transpose(arpeggio(X) ,7) ) +transpose((X+transpose(X,12) ) ,12) ) +arpeggio(transpose((shuffle(X) +transpose(arpeggio(X) ,12) ) ,4) ) ) ) ,4) +transpose(transpose(arpeggio(echo(shuffle(X) ,4,6) ) ,-7) ,-5) ) ) +transpose((transpose(transpose(transpose((transpose(arpeggio(transpose((X+transpose(X,7) ) ,4) ) ,-5) |echo(transpose(X,4) ,4,6) ) ,-7) ,4) ,4) +transpose(transpose(((arpeggio(step(transpose(transpose(transpose(X,4) ,-5) ,-5) ,12) ) +echo(echo(step(arpeggio(X) ,12) ,4,6) ,4,6) ) +((transpose(X,-7) |X) +transpose(step((X|X) ,12) ,7) ) ) ,4) ,7) ) ,12) ) +transpose((transpose(shuffle((transpose((X|X) ,-7) +transpose(transpose(arpeggio(transpose(transpose(X,4) ,-7) ) ,-5) ,12) ) ) ,-5) +(((transpose(transpose(shuffle(((X|X) +step(X,12) ) ) ,-7) ,4) +transpose(((shuffle(shuffle(X) ) +transpose((transpose(X,4) |echo(X,4,6) ) ,4) ) +transpose((X|X) ,7) ) ,-7) ) +transpose(transpose((transpose((X+transpose(X,7) ) ,4) |step(((X+(X|X) ) |X) ,12) ) ,4) ,4) ) +transpose(transpose(arpeggio((transpose(X,-7) +X) ) ,4) ,7) ) ) ,12) ) ,4) +transpose(step(transpose(transpose(transpose((((transpose(transpose(shuffle(((X|X) +transpose(transpose(X,-7) ,7) ) ) ,-5) ,-5) +transpose(step(((X+(X+X) ) +(X+(X+transpose(X,12) ) ) ) ,12) ,4) ) +transpose(((((X+transpose((X|X) ,4) ) +transpose(X,7) ) +transpose(echo(step(X,12) ,4,6) ,7) ) +transpose(((((X|X) +transpose((X+X) ,4) ) +transpose(X,7) ) +transpose(echo(X,4,6) ,4) ) ,12) ) ,7) ) +(((transpose(X,-5) +transpose(((X+transpose(X,4) ) +transpose(X,7) ) ,12) ) |((X+transpose(X,12) ) +X) ) +(arpeggio((X+transpose(X,12) ) ) +transpose(X,12) ) ) ) ,4) ,-7) ,-5) ,12) ,7) ) +transpose((((echo((step(((transpose(transpose(X,4) ,-5) +transpose(((((X|X) |X) +transpose(echo(X,4,6) ,4) ) +transpose(transpose(X,-5) ,7) ) ,4) ) +transpose(transpose(transpose(X,4) ,-5) ,7) ) ,12) |transpose(transpose(transpose((transpose(X,4) +step(echo(X,4,6) ,12) ) ,4) ,4) ,-5) ) ,4,6) +transpose(transpose((((((echo((shuffle(X) +transpose(X,7) ) ,4,6) |echo(X,4,6) ) +transpose((transpose(X,-7) |transpose((X+transpose(X,-7) ) ,-5) ) ,4) ) +transpose(transpose(transpose(transpose((X+transpose(X,12) ) ,-7) ,4) ,-7) ,7) ) |(step(shuffle(step((X+X) ,12) ) ,12) +transpose(arpeggio(X) ,4) ) ) +transpose((shuffle(echo(echo(shuffle(transpose(X,4) ) ,4,6) ,4,6) ) +(transpose((X|(((transpose(X,-5) +X) +transpose(transpose(transpose(X,4) ,4) ,7) ) |(transpose(X,-5) +(X+X) ) ) ) ,-7) +transpose(((((arpeggio(X) +transpose((X+transpose(X,7) ) ,12) ) |(((((X+transpose(X,4) ) +transpose(X,7) ) +transpose(((X+transpose(X,4) ) +transpose(X,7) ) ,4) ) +transpose((X|X) ,7) ) +transpose(((X+X) +X) ,12) ) ) +transpose(transpose(transpose(transpose(X,-5) ,-7) ,-7) ,12) ) +transpose(transpose(((transpose(X,4) |X) +transpose((X|X) ,-7) ) ,-5) ,12) ) ,12) ) ) ,7) ) ,-5) ,4) ) +transpose((transpose(((X|echo(transpose(X,-5) ,4,6) ) +transpose(X,-5) ) ,4) +(echo(transpose(transpose(transpose(echo(X,4,6) ,4) ,4) ,-5) ,4,6) +transpose(transpose(transpose((X|X) ,-5) ,-7) ,12) ) ) ,7) ) +transpose((((transpose(transpose(echo(X,4,6) ,-7) ,4) +echo(transpose(transpose((X|X) ,-5) ,-7) ,4,6) ) +transpose((arpeggio((arpeggio((step(shuffle(X) ,12) +echo((X|X) ,4,6) ) ) |transpose(transpose(((X+transpose(X,4) ) +transpose(X,7) ) ,-7) ,-5) ) ) +((((X+transpose(X,7) ) +transpose(transpose(transpose(transpose(X,-7) ,4) ,-7) ,7) ) +transpose(transpose(shuffle(arpeggio((X+X) ) ) ,-5) ,12) ) +transpose((shuffle(X) +transpose(transpose(((X+transpose(X,4) ) +transpose(X,7) ) ,4) ,7) ) ,12) ) ) ,7) ) +transpose(((transpose((transpose((X|X) ,4) +step((X+transpose(X,12) ) ,12) ) ,-7) +arpeggio(arpeggio(transpose(transpose(((X|X) +transpose(transpose((X|X) ,-5) ,12) ) ,-5) ,4) ) ) ) +transpose(step(shuffle(((transpose(X,-7) +transpose(transpose(X,-7) ,12) ) +transpose(transpose(transpose(X,-7) ,-7) ,12) ) ) ,12) ,12) ) ,7) ) ,7) ) ,4) ) +transpose(step(((echo((transpose(transpose(transpose((X+transpose((X+X) ,12) ) ,4) ,-7) ,4) +transpose((((transpose(X,4) |(shuffle((X+X) ) |X) ) |((X+transpose(X,7) ) |transpose(((X+transpose(X,4) ) +transpose(X,7) ) ,4) ) ) +transpose((X+(transpose((X+X) ,4) +step(X,12) ) ) ,4) ) ,7) ) ,4,6) +transpose(transpose(((arpeggio((arpeggio((X+transpose(X,12) ) ) +transpose(transpose((X+transpose(X,7) ) ,-7) ,-7) ) ) +transpose(transpose(((arpeggio(((X+X) |X) ) +transpose(transpose((arpeggio(X) +transpose((X|X) ,12) ) ,-7) ,4) ) +transpose(transpose((((X+X) +transpose(X,-5) ) +transpose(arpeggio(X) ,7) ) ,-5) ,7) ) ,-5) ,4) ) +transpose(arpeggio((transpose((transpose(X,-7) |X) ,-5) +transpose(echo(((X+step(X,12) ) +transpose((X|X) ,7) ) ,4,6) ,12) ) ) ,7) ) ,4) ,7) ) +transpose(transpose(transpose(echo((transpose(((X+(X+X) ) +transpose((transpose(X,4) |(X+transpose(X,7) ) ) ,12) ) ,4) +transpose(transpose(((echo(X,4,6) +transpose(shuffle(X) ,7) ) +((transpose(X,-7) +transpose(transpose(X,4) ,4) ) +transpose((X+transpose(X,12) ) ,7) ) ) ,4) ,12) ) ,4,6) ,-5) ,-7) ,7) ) ,12) ,7) ) ) ,-5) +transpose((shuffle((((((X+arpeggio(X) ) +shuffle(X) ) +transpose(arpeggio((X+transpose(shuffle(X) ,7) ) ) ,4) ) +transpose(((echo(transpose(transpose(X,4) ,4) ,4,6) |transpose((X+transpose(X,7) ) ,-5) ) +transpose(transpose(((((X+transpose(X,4) ) +transpose(X,7) ) |shuffle((X|X) ) ) |((transpose(X,-7) |X) |X) ) ,-5) ,7) ) ,12) ) +transpose((((((X+X) +transpose(transpose(((X+X) +transpose(X,7) ) ,-5) ,7) ) +transpose((step(X,12) +transpose((X|X) ,7) ) ,4) ) +transpose(transpose(transpose((step(X,12) |X) ,-5) ,4) ,7) ) |(transpose(echo(((X+transpose(X,7) ) +transpose((X+transpose(X,7) ) ,7) ) ,4,6) ,-5) +transpose(arpeggio(echo(transpose((X+transpose(X,12) ) ,4) ,4,6) ) ,12) ) ) ,12) ) ) +transpose(transpose(transpose((((transpose(arpeggio(step((X+transpose(echo(X,4,6) ,12) ) ,12) ) ,4) +transpose(((((step(transpose(X,-7) ,12) +transpose(((X|X) |(X+X) ) ,7) ) |(transpose(X,-7) |(X|X) ) ) +transpose((step((transpose(arpeggio(arpeggio(X) ) ,-5) +(transpose(X,4) +arpeggio(X) ) ) ,12) +transpose(transpose(transpose(transpose(arpeggio(X) ,-7) ,-5) ,4) ,12) ) ,4) ) +transpose(transpose(transpose((transpose(echo(X,4,6) ,-7) |echo(transpose(transpose(X,-5) ,4) ,4,6) ) ,-7) ,4) ,7) ) ,12) ) +transpose(((arpeggio((((transpose(X,4) +(X+X) ) +transpose(((arpeggio(X) +(X+transpose(X,12) ) ) +transpose(transpose(X,4) ,12) ) ,4) ) +transpose(((transpose(X,-7) +transpose((X+transpose(X,7) ) ,7) ) |(((X+transpose(X,7) ) +transpose((X+transpose(X,12) ) ,4) ) +transpose(X,7) ) ) ,7) ) ) +step(transpose(transpose((X+transpose(echo(X,4,6) ,12) ) ,4) ,-7) ,12) ) +transpose(echo(((transpose(transpose(transpose((X+X) ,-7) ,4) ,4) +shuffle(((X+X) +transpose(X,7) ) ) ) |(transpose(transpose((X|X) ,4) ,4) |(arpeggio(step(arpeggio(X) ,12) ) +echo(transpose(X,-5) ,4,6) ) ) ) ,4,6) ,7) ) ,4) ) +transpose(transpose(((transpose(((((X+transpose(X,4) ) +transpose(X,7) ) +X) +transpose(shuffle(X) ,7) ) ,4) +transpose((((X+transpose(shuffle(X) ,12) ) +transpose((X+echo(transpose((X+transpose(X,12) ) ,4) ,4,6) ) ,4) ) +transpose(((transpose(echo(X,4,6) ,-5) +transpose(arpeggio((X+transpose(X,7) ) ) ,4) ) +transpose((X|X) ,7) ) ,7) ) ,7) ) +transpose((((((shuffle(X) +transpose(step((arpeggio(X) +transpose(X,7) ) ,12) ,4) ) +transpose(arpeggio(X) ,7) ) +transpose(transpose(echo((X+transpose(X,12) ) ,4,6) ,-5) ,12) ) +transpose(((X+transpose(transpose(X,-7) ,12) ) |(((X+transpose(X,4) ) +transpose(X,7) ) +transpose((X+X) ,12) ) ) ,4) ) +transpose((((X+transpose(transpose(X,4) ,4) ) +transpose((X+transpose(X,7) ) ,7) ) +transpose((X+transpose(X,7) ) ,-7) ) ,7) ) ,7) ) ,-7) ,7) ) ,-5) ,4) ,7) ) ,4) ) +transpose(transpose(((((((((transpose(X,4) +(X+transpose(X,12) ) ) +shuffle(((X+X) +transpose(X,4) ) ) ) +transpose(transpose((((X+transpose(transpose(X,-7) ,7) ) +X) +transpose((transpose(X,-7) +transpose(transpose(transpose(transpose(X,4) ,-7) ,-5) ,7) ) ,12) ) ,4) ,4) ) +transpose(transpose((X+transpose(X,12) ) ,-7) ,7) ) +transpose(transpose(step(transpose((X+transpose(X,7) ) ,-5) ,12) ,4) ,7) ) +transpose(transpose(arpeggio(transpose((arpeggio(((((X|X) +transpose(X,12) ) +transpose(transpose((X+X) ,-7) ,4) ) +transpose(X,7) ) ) +echo(X,4,6) ) ,-7) ) ,-5) ,7) ) +transpose((transpose(arpeggio(((X|X) |transpose(X,4) ) ) ,4) +transpose(((X+transpose(X,12) ) +transpose((((X+transpose(X,12) ) +transpose(X,7) ) +transpose((transpose(X,-5) +transpose(step(X,12) ,7) ) ,7) ) ,7) ) ,-5) ) ,12) ) +transpose(((step(transpose((X|X) ,-7) ,12) +transpose((step(transpose(X,-5) ,12) +(transpose((X|X) ,4) +transpose(transpose(X,4) ,12) ) ) ,12) ) +transpose((transpose(((X+transpose(X,7) ) +transpose((transpose(X,4) |transpose((X|X) ,4) ) ,7) ) ,4) +transpose((echo(transpose(step(X,12) ,-5) ,4,6) +X) ,12) ) ,12) ) ,-5) ) ,-5) ,7) ) ) +transpose(transpose(arpeggio(arpeggio(shuffle(shuffle((transpose(((transpose(transpose((transpose(arpeggio(transpose(X,-7) ) ,-5) +transpose((X+transpose(X,12) ) ,7) ) ,4) ,-5) |transpose((transpose((transpose(((X+X) +transpose(shuffle(X) ,12) ) ,-5) +transpose((transpose(X,4) +transpose(X,12) ) ,12) ) ,-5) +transpose((X|((X+transpose(X,4) ) +transpose(X,7) ) ) ,7) ) ,-7) ) +transpose((shuffle(transpose(echo((transpose((transpose(X,-5) |X) ,-5) +transpose((arpeggio(X) |step(X,12) ) ,12) ) ,4,6) ,4) ) |((arpeggio(X) +transpose((X+(X|X) ) ,4) ) +transpose(transpose(step(step(shuffle(X) ,12) ,12) ,-5) ,7) ) ) ,12) ) ,4) +transpose(transpose(transpose(step(echo((transpose((transpose(arpeggio(X) ,-7) +transpose((X+transpose(echo(X,4,6) ,12) ) ,7) ) ,-7) |(step(step(X,12) ,12) +step((X|X) ,12) ) ) ,4,6) ,12) ,4) ,-5) ,4) ) ) ) ) ) ,-5) ,7) )
random seed used was 23

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