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:
Randomize patches:
 

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After 20 generations the expression "X" became this:
transpose((transpose(echo((shuffle(arpeggio(((shuffle((arpeggio((X+transpose(X,12) ) ) +transpose(X,-5) ) ) +transpose((((X+transpose(transpose(X,-7) ,4) ) +transpose(arpeggio(X) ,7) ) +shuffle((X+X) ) ) ,4) ) +transpose(transpose(transpose(echo(X,4,6) ,4) ,-5) ,7) ) ) ) +transpose((transpose((shuffle((step(step(arpeggio(X) ,12) ,12) +transpose((echo((((X+transpose(X,7) ) +transpose(transpose(X,-5) ,4) ) +transpose((X+transpose(X,12) ) ,7) ) ,4,6) +transpose(transpose(transpose(X,4) ,-7) ,7) ) ,12) ) ) +((transpose(shuffle(((shuffle(X) +transpose(((((((X|X) +(X+X) ) +transpose((X+transpose(transpose(X,-7) ,12) ) ,4) ) +transpose(transpose(transpose(X,-5) ,-7) ,7) ) +transpose(transpose((((transpose(X,-7) +transpose((X|X) ,4) ) +transpose(X,7) ) +transpose(transpose(transpose(X,-5) ,-5) ,7) ) ,-7) ,4) ) +transpose(transpose(X,4) ,7) ) ,4) ) +transpose(transpose(X,4) ,7) ) ) ,-5) +transpose(step((((shuffle(transpose(shuffle(X) ,4) ) +transpose((X+transpose(X,12) ) ,4) ) +transpose(shuffle(X) ,7) ) |transpose((echo((transpose(X,-7) |arpeggio(X) ) ,4,6) |echo(echo((echo(X,4,6) |X) ,4,6) ,4,6) ) ,-5) ) ,12) ,4) ) +transpose((((shuffle(transpose(transpose(X,4) ,-7) ) +transpose((transpose((X+X) ,-5) |shuffle((transpose((X|X) ,-7) +X) ) ) ,12) ) +transpose(arpeggio(shuffle(transpose((X+transpose(X,7) ) ,4) ) ) ,12) ) +transpose((transpose(((transpose((X+X) ,-7) +transpose((X+transpose(X,7) ) ,7) ) +transpose(X,7) ) ,-5) |transpose(shuffle(((shuffle(X) +transpose(shuffle(transpose(X,4) ) ,7) ) +transpose(transpose((transpose((X+X) ,4) +transpose(X,12) ) ,4) ,7) ) ) ,-5) ) ,12) ) ,7) ) ) ,-7) +transpose(shuffle((shuffle(shuffle(((transpose(arpeggio(X) ,-7) +transpose(((X+transpose(X,4) ) +transpose(shuffle(arpeggio(X) ) ,12) ) ,7) ) |(echo(echo(X,4,6) ,4,6) +transpose(shuffle(shuffle(transpose(X,-7) ) ) ,-5) ) ) ) ) +transpose(echo((((shuffle(arpeggio(transpose(transpose(X,-7) ,-5) ) ) +transpose(arpeggio(transpose((X+transpose(X,12) ) ,4) ) ,4) ) +transpose((step(shuffle(X) ,12) +X) ,7) ) +transpose(shuffle(shuffle(arpeggio(shuffle(((X+X) +arpeggio(X) ) ) ) ) ) ,7) ) ,4,6) ,12) ) ) ,7) ) ,12) ) ,4,6) ,-7) |(((((step(transpose(transpose((((shuffle((((X+transpose((X+transpose(X,12) ) ,4) ) +transpose(shuffle(X) ,7) ) +transpose(X,-7) ) ) +transpose(((transpose((X|X) ,-5) +transpose(transpose((X|(X+transpose(X,12) ) ) ,-5) ,7) ) |(arpeggio(X) +transpose(transpose((X|X) ,4) ,12) ) ) ,4) ) +transpose(transpose(((X+transpose(X,7) ) +transpose(transpose(X,-7) ,12) ) ,-7) ,7) ) |step(((shuffle(shuffle(transpose((X|X) ,-5) ) ) +((((step(X,12) +transpose(shuffle(X) ,4) ) +transpose(transpose(X,-7) ,7) ) +((X+transpose(X,12) ) +X) ) |transpose(X,-5) ) ) +transpose(transpose((shuffle(X) +transpose(step(transpose(step(X,12) ,-7) ,12) ,7) ) ,4) ,12) ) ,12) ) ,-5) ,-5) ,12) +transpose(transpose(((step(transpose((((transpose(X,4) |(X+transpose(X,12) ) ) +transpose(shuffle(((X+transpose(X,4) ) +transpose(X,7) ) ) ,4) ) +transpose((X|(X+transpose(X,12) ) ) ,7) ) ,-5) ,12) +transpose((((echo(X,4,6) +(X+X) ) +transpose((shuffle(transpose(X,-7) ) |X) ,7) ) +transpose(transpose(((shuffle(shuffle(((X+transpose(X,12) ) |shuffle(X) ) ) ) +(X+transpose((((X+transpose(X,4) ) +transpose(X,7) ) |transpose((X+X) ,4) ) ,7) ) ) +shuffle(shuffle(transpose((transpose((X+transpose(X,12) ) ,4) +transpose(X,-5) ) ,-5) ) ) ) ,4) ,4) ) ,4) ) +transpose(transpose(shuffle(((((X+transpose(X,4) ) +transpose(arpeggio(transpose(X,4) ) ,7) ) +transpose((X|X) ,12) ) +transpose(transpose(step((X|X) ,12) ,-5) ,-5) ) ) ,-7) ,7) ) ,4) ,12) ) +transpose(shuffle((((transpose(transpose((transpose(((transpose(shuffle(X) ,-5) +echo(shuffle(X) ,4,6) ) +shuffle(transpose(X,4) ) ) ,4) |transpose((echo(transpose(X,-5) ,4,6) +transpose(transpose(echo(shuffle((X+X) ) ,4,6) ,-7) ,7) ) ,4) ) ,-7) ,4) |transpose((transpose(X,4) +transpose(X,12) ) ,-7) ) +transpose(transpose(((transpose(transpose(((shuffle(shuffle(X) ) |transpose(X,-7) ) |transpose(transpose(X,4) ,4) ) ,4) ,-5) +transpose(step(transpose((arpeggio((arpeggio(X) +transpose(transpose(X,-7) ,12) ) ) +transpose(transpose((X+X) ,-7) ,7) ) ,-5) ,12) ,4) ) +transpose(shuffle(((shuffle(transpose(shuffle(X) ,-7) ) |step(X,12) ) |((X+transpose(X,-7) ) +transpose(((X+transpose(X,4) ) +transpose(X,7) ) ,-5) ) ) ) ,7) ) ,-7) ,4) ) +transpose(step(transpose(transpose(transpose(X,-5) ,-7) ,-5) ,12) ,7) ) ) ,7) ) +shuffle(step(arpeggio(transpose((echo(shuffle(X) ,4,6) |transpose((shuffle(X) +transpose((X+X) ,7) ) ,-7) ) ,-7) ) ,12) ) ) +((shuffle(transpose((shuffle(transpose((((X+X) |transpose(X,4) ) +transpose(X,-5) ) ,-5) ) +transpose((shuffle(step(X,12) ) |X) ,-5) ) ,4) ) +(transpose(((step(((((step((X|X) ,12) +transpose(X,-7) ) +transpose((((X+transpose(X,7) ) +transpose(transpose(transpose(X,-5) ,-5) ,4) ) +transpose(transpose((X+transpose(X,12) ) ,4) ,7) ) ,12) ) +transpose((transpose(X,-7) |((X+X) +((X+transpose(X,4) ) +transpose(X,7) ) ) ) ,4) ) +transpose((((transpose((X+X) ,4) +echo((X|X) ,4,6) ) +transpose(arpeggio(((X+transpose(X,4) ) +transpose((X+transpose(X,7) ) ,7) ) ) ,4) ) +transpose(transpose(arpeggio((X+transpose(X,12) ) ) ,-5) ,7) ) ,7) ) ,12) +transpose((((X+transpose(X,12) ) +transpose(step(X,12) ,12) ) +transpose(X,-7) ) ,12) ) +transpose(transpose((transpose(transpose(arpeggio((X+X) ) ,-5) ,-7) +transpose(arpeggio(transpose(X,-5) ) ,4) ) ,-7) ,7) ) ,4) +shuffle((transpose(step(shuffle(echo((transpose(shuffle(X) ,-5) +transpose(X,12) ) ,4,6) ) ,12) ,-5) +transpose((shuffle(shuffle(((arpeggio(((X+transpose(X,7) ) +transpose(X,12) ) ) +transpose(arpeggio(transpose((transpose(transpose(X,4) ,4) +transpose((X|transpose(X,-7) ) ,12) ) ,4) ) ,4) ) +transpose(((shuffle((transpose(echo(X,4,6) ,-5) |echo(arpeggio(X) ,4,6) ) ) +transpose(arpeggio((X|X) ) ,4) ) +transpose(transpose(transpose(X,-7) ,4) ,7) ) ,7) ) ) ) +transpose(transpose(shuffle(echo(step((echo(X,4,6) |X) ,12) ,4,6) ) ,-7) ,12) ) ,7) ) ) ) ) +transpose(transpose(transpose((transpose(echo((transpose(echo(((X|X) +((X+transpose(X,4) ) +transpose(X,7) ) ) ,4,6) ,-5) |shuffle(transpose(X,4) ) ) ,4,6) ,4) +transpose(transpose(step(((shuffle(X) +transpose((X+X) ,7) ) +shuffle(shuffle(((X+transpose(X,12) ) +transpose(transpose(X,-5) ,7) ) ) ) ) ,12) ,-7) ,12) ) ,-7) ,-5) ,7) ) ) +((((arpeggio(arpeggio(shuffle(step(transpose((transpose(step(X,12) ,4) |arpeggio((X+X) ) ) ,-7) ,12) ) ) ) |transpose((transpose(arpeggio(X) ,-7) +transpose(shuffle(shuffle(X) ) ,-7) ) ,-7) ) +transpose(step(((arpeggio((echo(transpose(X,-7) ,4,6) |(X|(X+transpose(X,7) ) ) ) ) |arpeggio((transpose(X,-5) +(shuffle(X) +(X+X) ) ) ) ) |((echo(shuffle(transpose(X,4) ) ,4,6) |transpose(shuffle(transpose(X,-5) ) ,-7) ) +((X|X) +(X+transpose(X,12) ) ) ) ) ,12) ,12) ) +transpose((transpose(transpose(step(step(transpose(echo(arpeggio(X) ,4,6) ,-5) ,12) ,12) ,-7) ,-7) +step(((((((shuffle(step((transpose(X,-7) +(X|X) ) ,12) ) +transpose((((transpose(step(transpose(X,-7) ,12) ,-7) +transpose(shuffle(transpose(X,-5) ) ,7) ) +transpose((shuffle((step(X,12) |shuffle(X) ) ) |echo(step(X,12) ,4,6) ) ,7) ) +transpose(echo(((X+X) +transpose(X,4) ) ,4,6) ,-7) ) ,4) ) +transpose(transpose(((shuffle(transpose(X,-5) ) |shuffle(((X+X) +transpose(X,-7) ) ) ) +shuffle((transpose(transpose(X,-7) ,4) +transpose((transpose(X,-7) +(X|X) ) ,12) ) ) ) ,4) ,7) ) |shuffle(((((arpeggio(X) +transpose((X+transpose(X,12) ) ,4) ) +transpose(transpose(X,4) ,7) ) +step((transpose(X,4) |transpose(X,-7) ) ,12) ) +transpose(transpose(transpose(((X|X) |(transpose(X,4) |step(X,12) ) ) ,-5) ,-7) ,7) ) ) ) +transpose(arpeggio(step(((shuffle(echo((X+X) ,4,6) ) +transpose(transpose((echo((X+transpose(X,7) ) ,4,6) +(X+transpose(arpeggio(X) ,12) ) ) ,4) ,4) ) +transpose((shuffle(transpose((X+transpose(X,12) ) ,-7) ) +transpose(arpeggio((X+(X+X) ) ) ,7) ) ,7) ) ,12) ) ,4) ) +transpose(((((((X+transpose(X,7) ) |echo(X,4,6) ) +X) +transpose(shuffle(((X+transpose(X,4) ) +transpose(X,7) ) ) ,7) ) |echo((transpose(X,-5) +transpose(transpose(X,-7) ,12) ) ,4,6) ) |transpose((transpose(shuffle(echo(X,4,6) ) ,-7) |transpose((X|arpeggio(X) ) ,-5) ) ,-5) ) ,7) ) |(transpose(step(shuffle(shuffle(((X+transpose(((X+transpose(X,4) ) +transpose(X,7) ) ,4) ) +transpose((X+transpose(X,12) ) ,7) ) ) ) ,12) ,4) +transpose((((transpose(X,-5) |(X+transpose(echo(X,4,6) ,7) ) ) +transpose(shuffle(echo(X,4,6) ) ,7) ) +transpose(arpeggio(step((X+X) ,12) ) ,12) ) ,12) ) ) ,12) ) ,12) ) +transpose((transpose(((transpose(arpeggio(echo(transpose(X,4) ,4,6) ) ,-5) +transpose(((step(transpose(((((X|X) |((X+transpose(X,4) ) +transpose(X,7) ) ) +transpose(((X|X) |shuffle(X) ) ,4) ) |transpose(shuffle(((X|transpose(X,4) ) +X) ) ,-7) ) ,4) ,12) +transpose((transpose(arpeggio(echo((X+X) ,4,6) ) ,-7) +transpose(transpose(((X+transpose((X+X) ,7) ) +transpose((X+X) ,7) ) ,4) ,-5) ) ,4) ) +transpose((shuffle(transpose(transpose(arpeggio(X) ,-5) ,4) ) +echo(((X+(X+X) ) |transpose(X,-5) ) ,4,6) ) ,7) ) ,4) ) +transpose(transpose(((shuffle(transpose(X,-5) ) |X) |((((X+transpose(X,7) ) +transpose((X+X) ,12) ) +transpose(shuffle(X) ,4) ) +transpose((X+(X+transpose(echo(X,4,6) ,7) ) ) ,7) ) ) ,4) ,7) ) ,4) +(arpeggio(arpeggio((transpose(shuffle(((X|X) +transpose(shuffle(transpose(X,4) ) ,7) ) ) ,-7) +transpose((shuffle(((((X+X) |transpose(X,-5) ) +transpose(((X+transpose(X,7) ) +transpose(transpose(X,-7) ,7) ) ,12) ) +transpose(step(step(arpeggio(X) ,12) ,12) ,7) ) ) +transpose(((X+transpose(X,12) ) +(((X+X) |transpose(X,-5) ) |transpose(((X+transpose(X,4) ) +transpose(X,7) ) ,-5) ) ) ,-7) ) ,7) ) ) ) +transpose(step(transpose(transpose((((transpose(X,-5) |step(transpose((arpeggio(X) +transpose(X,12) ) ,-7) ,12) ) +shuffle((X+X) ) ) |transpose(X,-7) ) ,-7) ,-5) ,12) ,7) ) ) ,7) ) ) ) ,-5)
random seed used was 229786292

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