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(((arpeggio(transpose(transpose(step((transpose(transpose(echo(shuffle(X) ,4,6) ,4) ,4) +arpeggio(step(transpose((((transpose(X,-5) +transpose((transpose(echo(X,4,6) ,-7) |transpose((transpose(X,-7) +transpose(transpose(X,4) ,7) ) ,-5) ) ,7) ) +transpose(shuffle(transpose(step(X,12) ,4) ) ,4) ) +transpose(step((transpose(X,4) +arpeggio((X+transpose(X,12) ) ) ) ,12) ,7) ) ,-7) ,12) ) ) ,12) ,4) ,4) ) |step(((((((transpose((arpeggio(transpose((echo(X,4,6) +transpose((X+X) ,7) ) ,4) ) +transpose((X+transpose(arpeggio(X) ,12) ) ,-5) ) ,-5) +((echo((X+transpose(transpose(X,-7) ,7) ) ,4,6) +transpose(((transpose((transpose(X,4) +(X+X) ) ,4) |transpose(transpose(transpose(X,-7) ,-5) ,-5) ) +transpose(((X+transpose(transpose(X,-7) ,-5) ) +transpose(transpose(((X|(X+X) ) +transpose(X,4) ) ,4) ,12) ) ,12) ) ,4) ) +transpose((arpeggio(transpose(shuffle(X) ,-5) ) |echo(((X|X) |transpose(X,4) ) ,4,6) ) ,7) ) ) +transpose((transpose(((shuffle(((X|transpose(X,-5) ) |(transpose(X,4) +transpose(X,7) ) ) ) +transpose(transpose(echo(transpose(echo(transpose(X,4) ,4,6) ,4) ,4,6) ,4) ,7) ) +arpeggio((((transpose(arpeggio(X) ,-7) +transpose((X+transpose(X,7) ) ,4) ) +transpose((X+transpose(step(X,12) ,7) ) ,7) ) +transpose(transpose((((X+transpose(X,4) ) +transpose(X,7) ) +transpose(shuffle(X) ,7) ) ,-7) ,12) ) ) ) ,-7) +transpose(transpose((((arpeggio((X|X) ) +transpose((transpose(X,-7) +transpose(transpose((X|X) ,4) ,7) ) ,4) ) +transpose(transpose((((X|X) +transpose(step(X,12) ,4) ) +transpose(transpose((X+transpose(X,12) ) ,-5) ,7) ) ,-5) ,7) ) |arpeggio(shuffle(X) ) ) ,-5) ,7) ) ,7) ) +transpose(transpose((step((echo(X,4,6) +transpose(X,4) ) ,12) +transpose(((transpose(X,-5) +transpose(transpose(X,-7) ,4) ) +transpose(echo(X,4,6) ,7) ) ,-5) ) ,4) ,4) ) +transpose(((transpose(transpose(transpose((((X+transpose(X,-7) ) +transpose((X|X) ,4) ) +transpose((transpose(X,4) +transpose(transpose(X,-7) ,12) ) ,7) ) ,4) ,-5) ,-5) +transpose(shuffle(((transpose(((transpose(X,-5) |(X|X) ) +(X|transpose(X,-7) ) ) ,-7) +transpose(transpose(X,-5) ,-5) ) |((((transpose(X,-5) +X) +transpose((X+transpose(X,12) ) ,4) ) +transpose((X+X) ,7) ) |X) ) ) ,-5) ) +transpose(echo(shuffle((step(((echo(X,4,6) +transpose(transpose(transpose(X,-5) ,-7) ,4) ) +transpose(((X+transpose(X,7) ) |X) ,7) ) ,12) +transpose((transpose((X|X) ,-7) +transpose((((((X+transpose(X,4) ) +transpose(X,7) ) +transpose((X|X) ,-7) ) +transpose(transpose(X,-5) ,4) ) +transpose(transpose(X,-5) ,7) ) ,12) ) ,12) ) ) ,4,6) ,7) ) ,7) ) +transpose(transpose(step(((((transpose(((((X+transpose(X,4) ) +transpose(X,7) ) +transpose(X,4) ) +transpose(X,7) ) ,4) +transpose(echo((X+transpose(X,12) ) ,4,6) ,12) ) +transpose(transpose(transpose((X|X) ,-7) ,-5) ,4) ) +transpose(transpose((transpose(X,4) |(X|X) ) ,4) ,7) ) +transpose(arpeggio((X+(X+X) ) ) ,12) ) ,12) ,4) ,12) ) +transpose(((transpose(transpose(step(shuffle(step(((X+X) |transpose(X,-7) ) ,12) ) ,12) ,-7) ,-5) |step(((((X+transpose(transpose(((X+transpose(X,4) ) +transpose(arpeggio(X) ,7) ) ,4) ,12) ) +transpose(transpose((X|X) ,-5) ,12) ) +transpose((shuffle(X) +(X+transpose(X,12) ) ) ,4) ) +transpose((echo(transpose(X,4) ,4,6) |(transpose(((X|X) +transpose(transpose(X,-7) ,4) ) ,-7) |echo(transpose(echo(X,4,6) ,-5) ,4,6) ) ) ,7) ) ,12) ) +transpose(((shuffle(arpeggio(echo(X,4,6) ) ) +transpose((step((X|X) ,12) |(((X|X) +transpose(X,12) ) +transpose(echo(X,4,6) ,12) ) ) ,12) ) +transpose(shuffle((transpose(X,-7) +(step(X,12) |echo(X,4,6) ) ) ) ,-5) ) ,7) ) ,7) ) ,12) ) +transpose((transpose(transpose(transpose(transpose(echo(transpose(echo(X,4,6) ,4) ,4,6) ,4) ,-7) ,4) ,-5) +transpose((step((transpose(arpeggio(((transpose(X,-7) +transpose(shuffle(X) ,7) ) +transpose((X+transpose((X+X) ,7) ) ,7) ) ) ,-5) |(transpose((transpose(X,4) +(step((X+transpose(X,7) ) ,12) +transpose(X,-5) ) ) ,-5) +transpose(((transpose((echo(X,4,6) |(transpose(X,-7) |transpose(X,-7) ) ) ,-7) +transpose((transpose((echo(X,4,6) +transpose((X|X) ,12) ) ,-5) +transpose(transpose(shuffle(transpose(X,-5) ) ,-7) ,7) ) ,12) ) +(step(transpose(transpose(X,4) ,4) ,12) +X) ) ,7) ) ) ,12) +transpose((transpose((arpeggio((arpeggio(transpose(X,-5) ) +(shuffle(arpeggio(transpose(X,4) ) ) +transpose((step(transpose(X,4) ,12) +transpose(echo(((X+transpose(X,4) ) +transpose(X,7) ) ,4,6) ,12) ) ,12) ) ) ) +transpose(transpose(echo(((X|X) +transpose(step(step(X,12) ,12) ,4) ) ,4,6) ,-7) ,-7) ) ,-5) +transpose(((((transpose(step(((X+transpose(X,4) ) +transpose(X,7) ) ,12) ,-7) |shuffle(transpose(X,-7) ) ) +transpose(echo((X+X) ,4,6) ,12) ) |transpose((step((X+step(X,12) ) ,12) +step(transpose((((step(X,12) +transpose(X,4) ) +transpose(transpose(X,-5) ,7) ) |transpose((X+X) ,-7) ) ,4) ,12) ) ,4) ) |echo(echo(arpeggio(transpose(echo((transpose(transpose(X,-5) ,4) |step((X+X) ,12) ) ,4,6) ,-5) ) ,4,6) ,4,6) ) ,7) ) ,-7) ) ,7) ) ,12) ) ,-7) ,-5) |arpeggio(((transpose(arpeggio(transpose(transpose(transpose(transpose(shuffle(((transpose(shuffle(X) ,4) |(echo((X|X) ,4,6) +transpose(transpose(X,4) ,12) ) ) +transpose((transpose((X+transpose(X,12) ) ,4) +(X+transpose(X,4) ) ) ,-5) ) ) ,-5) ,-7) ,4) ,4) ) ,-5) +step((transpose(shuffle((transpose(transpose(transpose(transpose(X,-5) ,-5) ,-5) ,-7) +transpose(shuffle((X+transpose(X,7) ) ) ,-7) ) ) ,4) +transpose(shuffle(echo(transpose(arpeggio((transpose(transpose((transpose(X,4) |X) ,-5) ,4) |transpose(((X|X) +transpose(X,7) ) ,-7) ) ) ,4) ,4,6) ) ,12) ) ,12) ) +transpose((echo(step(((((transpose(transpose(transpose((transpose(transpose((echo(X,4,6) |X) ,4) ,-5) +transpose(transpose(X,4) ,7) ) ,-7) ,-5) ,-7) +transpose(((((transpose(transpose((X+X) ,4) ,-7) +transpose(transpose(transpose(X,4) ,-5) ,4) ) +transpose(transpose(((X+transpose(X,4) ) +transpose(X,7) ) ,-7) ,7) ) |X) |transpose(transpose(((X+transpose(X,4) ) +transpose(X,7) ) ,-7) ,4) ) ,7) ) +(shuffle(echo((X+transpose(X,-5) ) ,4,6) ) +transpose(step((((X+X) |transpose(X,-5) ) +transpose((transpose(transpose(X,-5) ,4) +(X+transpose(transpose(X,-5) ,7) ) ) ,12) ) ,12) ,7) ) ) +transpose(transpose(transpose(transpose((transpose(echo(shuffle(echo((X+X) ,4,6) ) ,4,6) ,4) +transpose(((X+X) |shuffle(X) ) ,4) ) ,-5) ,-5) ,4) ,12) ) +(transpose(((((step((transpose(X,4) +transpose(X,7) ) ,12) +transpose(transpose((((X|X) +transpose(X,4) ) +transpose((X+transpose(X,7) ) ,7) ) ,4) ,7) ) |(transpose(X,-5) +echo((X+transpose(shuffle(X) ,7) ) ,4,6) ) ) +transpose((echo(transpose(((transpose(X,-7) |(X|X) ) +((transpose(X,4) +transpose(((X+transpose(X,4) ) +transpose(X,7) ) ,4) ) +transpose(X,7) ) ) ,-5) ,4,6) +transpose(X,-7) ) ,7) ) +(arpeggio((((X|X) +transpose(transpose(arpeggio(X) ,4) ,12) ) +X) ) +transpose(transpose((echo(X,4,6) |X) ,-7) ,-7) ) ) ,-5) +(arpeggio(((echo(transpose(X,-7) ,4,6) |((X+transpose(X,7) ) +transpose(X,12) ) ) +arpeggio((X+transpose(X,7) ) ) ) ) +transpose((transpose((transpose(X,4) |(((X+transpose(X,12) ) |((X+transpose(X,4) ) +transpose(X,7) ) ) +(transpose((X+transpose(X,12) ) ,-5) +((((X+X) +transpose(transpose(X,-5) ,4) ) +transpose((X|X) ,7) ) +echo((X+transpose(X,7) ) ,4,6) ) ) ) ) ,-7) |((arpeggio((X|X) ) |(shuffle(X) +transpose(((X|(X+X) ) +transpose(((X+X) |X) ,7) ) ,12) ) ) +arpeggio(echo(arpeggio(X) ,4,6) ) ) ) ,7) ) ) ) ,12) ,4,6) +transpose(shuffle((((transpose(echo(X,4,6) ,-5) +transpose(step(transpose(transpose((echo((X|X) ,4,6) |(step(X,12) +X) ) ,-5) ,-5) ,12) ,12) ) |(step(transpose(transpose((X+transpose(X,12) ) ,4) ,4) ,12) +transpose(transpose(transpose((((X+transpose(X,7) ) |X) +transpose(echo((X+transpose((X+transpose(X,12) ) ,12) ) ,4,6) ,7) ) ,4) ,4) ,7) ) ) |(transpose(((X|X) +(transpose(X,4) |transpose(X,4) ) ) ,-5) +((((X+X) +X) +transpose((transpose(X,4) +X) ,4) ) +transpose((X|X) ,7) ) ) ) ) ,12) ) ,7) ) ) )
random seed used was 73222987

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