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 20 generations the expression "X" became this:
(((((arpeggio(transpose(transpose(transpose(transpose((((X+transpose(X,4) ) +transpose(X,7) ) +transpose(step(X,12) ,7) ) ,-7) ,-7) ,-7) ,4) ) +transpose((transpose(arpeggio(transpose(transpose((arpeggio(transpose(X,-7) ) +transpose(shuffle((X+transpose(X,12) ) ) ,12) ) ,-7) ,-7) ) ,-5) +transpose(transpose((transpose(transpose((((arpeggio(X) +transpose(transpose(X,-5) ,4) ) +transpose((X+transpose(X,7) ) ,7) ) +transpose(transpose(step(X,12) ,-7) ,-7) ) ,4) ,-7) +(step(transpose(((X+transpose(X,7) ) |echo(X,4,6) ) ,-7) ,12) +echo(transpose((X+transpose(X,12) ) ,-7) ,4,6) ) ) ,-7) ,7) ) ,4) ) +transpose((step(transpose(transpose(transpose((transpose((X+transpose(X,12) ) ,-5) |((X+transpose(X,12) ) |echo(X,4,6) ) ) ,-5) ,-7) ,4) ,12) +transpose(((((arpeggio(transpose(transpose(((((echo((X+transpose(X,7) ) ,4,6) +(transpose(X,-7) |arpeggio(X) ) ) +transpose(((X+transpose(X,12) ) +transpose(X,12) ) ,4) ) +transpose(transpose(arpeggio(X) ,-5) ,4) ) +transpose(step(transpose(transpose(X,-5) ,4) ,12) ,7) ) ,-5) ,-7) ) +transpose(step(transpose(((arpeggio((step(X,12) +transpose((X+((X+(X+transpose(X,7) ) ) +transpose(((X+transpose(X,4) ) +transpose(X,7) ) ,7) ) ) ,12) ) ) +transpose(arpeggio((transpose(X,4) +transpose(transpose(X,-7) ,7) ) ) ,4) ) +transpose((step(((echo((transpose(X,4) +transpose(transpose(X,-7) ,12) ) ,4,6) +transpose((X+X) ,4) ) +transpose(transpose(arpeggio(echo(X,4,6) ) ,-5) ,7) ) ,12) |arpeggio(((transpose(X,-5) +transpose(arpeggio(step(X,12) ) ,4) ) +transpose((((X+transpose(shuffle(X) ,4) ) +transpose((X+transpose(X,7) ) ,7) ) +transpose(arpeggio(transpose(X,-5) ) ,7) ) ,7) ) ) ) ,7) ) ,-5) ,12) ,4) ) +transpose((step(echo(transpose((step(step(X,12) ,12) +transpose(echo(X,4,6) ,12) ) ,-7) ,4,6) ,12) +transpose(arpeggio(transpose((step(((X+transpose(X,4) ) +transpose(transpose(X,-7) ,7) ) ,12) |(((shuffle(X) +transpose(step(X,12) ,4) ) +transpose(transpose(X,4) ,7) ) +transpose(X,7) ) ) ,-7) ) ,12) ) ,7) ) |((step(transpose((echo(transpose(shuffle((transpose(X,-7) +transpose(arpeggio(X) ,12) ) ) ,-5) ,4,6) +transpose(((step(((((X|X) +transpose(X,4) ) +transpose(X,7) ) +transpose(echo(X,4,6) ,12) ) ,12) +transpose(echo(step(shuffle(echo(X,4,6) ) ,12) ,4,6) ,4) ) +transpose(transpose(echo(arpeggio((X+transpose(X,12) ) ) ,4,6) ,-5) ,7) ) ,7) ) ,-7) ,12) +transpose(shuffle((transpose(transpose(arpeggio(X) ,-5) ,-5) +transpose(((X+transpose(transpose(X,-5) ,4) ) +transpose((X|X) ,7) ) ,7) ) ) ,4) ) +transpose(transpose(transpose((X+transpose(X,12) ) ,-5) ,-5) ,7) ) ) +transpose(arpeggio(step((((echo(transpose(((X+transpose(X,4) ) +transpose(X,7) ) ,-7) ,4,6) +transpose((echo(transpose(X,-5) ,4,6) +transpose(transpose(transpose(shuffle(arpeggio(X) ) ,-7) ,-7) ,7) ) ,4) ) +transpose(arpeggio(((((transpose(X,-7) +transpose(transpose(X,-7) ,12) ) +transpose(transpose(X,-7) ,4) ) +transpose(transpose(X,-5) ,7) ) +transpose(echo(X,4,6) ,7) ) ) ,7) ) +transpose(((transpose(transpose(X,4) ,-7) +transpose(X,-7) ) +transpose(step(transpose(arpeggio(((X+transpose(X,4) ) +transpose(X,7) ) ) ,-7) ,12) ,7) ) ,12) ) ,12) ) ,7) ) ,12) ) ,7) ) +transpose(arpeggio(arpeggio(transpose(transpose(transpose(arpeggio(transpose(transpose(((transpose(X,-5) +transpose((((X|X) +transpose(transpose(transpose(X,-7) ,-5) ,4) ) +transpose(((transpose(X,-7) +transpose((X+transpose(X,7) ) ,4) ) +transpose(step(X,12) ,7) ) ,7) ) ,12) ) +transpose(shuffle((X+X) ) ,-5) ) ,-5) ,4) ) ,4) ,-7) ,4) ) ) ,12) ) +transpose(((((transpose(transpose(echo((echo(((transpose((transpose(X,-5) +transpose((X+transpose(X,7) ) ,7) ) ,-5) +transpose((((transpose(X,-5) +transpose(step((X+transpose(X,12) ) ,12) ,4) ) +transpose(((X+transpose(X,4) ) +transpose(X,7) ) ,7) ) |transpose((transpose(X,-5) +transpose(X,12) ) ,-7) ) ,4) ) +transpose((echo((X+X) ,4,6) +transpose((X+transpose(X,7) ) ,12) ) ,7) ) ,4,6) +((shuffle((((X+transpose(transpose(X,-5) ,12) ) +transpose(((step(X,12) +transpose(X,4) ) +transpose(X,7) ) ,4) ) +transpose(transpose(transpose(X,-5) ,-7) ,7) ) ) +(((X+transpose(X,4) ) +transpose(X,7) ) +transpose(transpose(((X+transpose(X,4) ) +transpose(X,7) ) ,-5) ,7) ) ) +transpose(arpeggio((((X|X) +transpose(shuffle(X) ,7) ) +transpose(shuffle(X) ,-5) ) ) ,7) ) ) ,4,6) ,-5) ,-7) +transpose((transpose((transpose(transpose((shuffle(echo(X,4,6) ) |(step(X,12) +transpose(shuffle(X) ,12) ) ) ,-7) ,4) +transpose(((((X+transpose(X,4) ) +transpose((X+transpose(X,12) ) ,7) ) +transpose(arpeggio((X+transpose(X,7) ) ) ,7) ) +transpose((((X+transpose(X,7) ) +transpose(X,12) ) +transpose(arpeggio(X) ,7) ) ,7) ) ,-7) ) ,-5) +transpose(shuffle(step(((echo(transpose((transpose(step(X,12) ,-7) +transpose(echo(X,4,6) ,12) ) ,-7) ,4,6) |transpose((arpeggio(X) +transpose(((step(X,12) +transpose((X+transpose(X,7) ) ,4) ) +transpose(shuffle(X) ,7) ) ,12) ) ,-7) ) +transpose(((echo(echo((shuffle(X) +(X+transpose(X,12) ) ) ,4,6) ,4,6) +transpose((((step(X,12) +transpose(echo(transpose(X,4) ,4,6) ,12) ) +transpose(arpeggio(((transpose((X+transpose(X,7) ) ,4) +transpose(transpose(X,-5) ,4) ) +transpose(((X+transpose(X,12) ) +transpose((X|(X+X) ) ,7) ) ,7) ) ) ,4) ) +transpose((((X+transpose(shuffle(X) ,4) ) +transpose(((X+transpose(X,4) ) +transpose(X,7) ) ,7) ) +((echo(transpose(X,-5) ,4,6) +transpose(transpose(X,-5) ,12) ) +transpose(((X+transpose(X,7) ) |step(X,12) ) ,12) ) ) ,7) ) ,4) ) +transpose((((shuffle(shuffle(X) ) |transpose(((step(X,12) +transpose((X+transpose(X,7) ) ,4) ) +transpose(X,7) ) ,-7) ) +transpose(arpeggio(step(X,12) ) ,4) ) +transpose(shuffle(transpose(transpose((X+transpose(X,12) ) ,-7) ,-5) ) ,7) ) ,7) ) ,12) ) ,12) ) ,7) ) ,7) ) +transpose(echo((transpose(transpose(((arpeggio(transpose((((X+transpose(X,7) ) +transpose(step(transpose(X,-5) ,12) ,7) ) +transpose(((((X|X) +X) +transpose(transpose((X+transpose(X,7) ) ,4) ,4) ) +transpose(shuffle(X) ,7) ) ,12) ) ,-7) ) +transpose(transpose(echo((X+transpose(X,12) ) ,4,6) ,-5) ,7) ) |transpose(shuffle(((transpose(((transpose(((((X+transpose(X,12) ) +transpose(transpose(X,-5) ,4) ) +transpose(echo(X,4,6) ,7) ) +transpose(echo(X,4,6) ,7) ) ,-7) +transpose(((transpose(X,-7) +transpose(X,7) ) +transpose(X,12) ) ,4) ) +transpose(step(X,12) ,7) ) ,-5) +transpose(transpose(((transpose(echo(X,4,6) ,-7) +transpose(transpose(echo(transpose(transpose(X,-5) ,-5) ,4,6) ,-7) ,4) ) +transpose(transpose(((step(X,12) +transpose(X,7) ) |transpose(X,-5) ) ,-7) ,7) ) ,-5) ,4) ) +transpose(echo(shuffle(X) ,4,6) ,7) ) ) ,-7) ) ,-7) ,-7) +transpose(transpose(transpose(((((((((transpose((echo(X,4,6) +arpeggio(X) ) ,-7) +transpose(step(transpose((transpose(X,-5) |transpose(X,-7) ) ,-7) ,12) ,4) ) +transpose(arpeggio(((X+X) +transpose(X,12) ) ) ,7) ) |(transpose(shuffle((X|X) ) ,-5) +transpose((((((X+transpose(X,12) ) +transpose(transpose(X,-5) ,12) ) +transpose(transpose(transpose(X,4) ,-7) ,12) ) +transpose(shuffle((transpose(X,-7) +transpose(X,7) ) ) ,4) ) +transpose((transpose(step(arpeggio(X) ,12) ,4) +transpose(arpeggio(X) ,12) ) ,7) ) ,7) ) ) +transpose(((((transpose(X,-7) +transpose(transpose(X,4) ,4) ) +transpose(X,7) ) +transpose(transpose(transpose(X,4) ,-5) ,12) ) +transpose(step(transpose((echo(((X+transpose(X,4) ) +transpose(X,7) ) ,4,6) +transpose((arpeggio(X) +X) ,7) ) ,-5) ,12) ,12) ) ,4) ) +transpose(transpose(transpose((transpose(echo((transpose(X,-7) +transpose(transpose(X,-5) ,12) ) ,4,6) ,-5) +transpose((X+((X+transpose(X,12) ) +(X+transpose(X,7) ) ) ) ,7) ) ,-5) ,-5) ,7) ) +transpose(transpose(transpose((transpose(transpose(X,-7) ,-7) +transpose(transpose(echo((X+transpose(X,7) ) ,4,6) ,4) ,7) ) ,-5) ,-5) ,4) ) +transpose(shuffle(transpose(arpeggio(step(transpose(X,4) ,12) ) ,4) ) ,7) ) |step((((shuffle(transpose(transpose(transpose(X,-7) ,-5) ,-7) ) |transpose(((X+transpose(X,4) ) +transpose(X,7) ) ,-5) ) +transpose((transpose(transpose((transpose(X,4) +transpose(step(X,12) ,7) ) ,-7) ,-5) +transpose((((X+transpose(X,4) ) +transpose(X,7) ) +transpose((transpose(arpeggio(X) ,-7) +X) ,12) ) ,12) ) ,7) ) |transpose(transpose((shuffle(transpose(X,4) ) +transpose(transpose(transpose(X,-5) ,-7) ,12) ) ,-7) ,4) ) ,12) ) ,-5) ,-7) ,12) ) ,4,6) ,4) ) +transpose(transpose(transpose(shuffle(echo((transpose((X+X) ,-5) +transpose(echo(shuffle(X) ,4,6) ,12) ) ,4,6) ) ,-7) ,-5) ,7) ) |step(transpose(arpeggio(transpose((arpeggio((arpeggio(((transpose((((X+transpose(X,4) ) +transpose(X,7) ) |X) ,4) +transpose(echo(transpose(transpose(X,-5) ,-5) ,4,6) ,12) ) |echo(transpose(echo(X,4,6) ,4) ,4,6) ) ) +transpose(transpose(((arpeggio(X) +transpose((((X+transpose(X,12) ) +transpose(transpose(X,-7) ,12) ) +transpose(((((((X+transpose(X,4) ) +transpose(X,7) ) +transpose((X+transpose(X,7) ) ,4) ) +transpose(X,7) ) +transpose(transpose(X,-7) ,4) ) +transpose(transpose((step(X,12) +transpose((X|X) ,12) ) ,-5) ,7) ) ,12) ) ,4) ) +transpose((transpose(echo(X,4,6) ,-7) +transpose(step(transpose(X,4) ,12) ,12) ) ,7) ) ,-7) ,12) ) ) +transpose(echo((((echo(transpose(X,-7) ,4,6) +transpose((arpeggio(echo((X|X) ,4,6) ) |(shuffle(transpose(X,-5) ) +transpose(transpose(transpose((X+transpose(X,12) ) ,4) ,-7) ,12) ) ) ,12) ) |transpose(transpose(((echo(X,4,6) +transpose(step(X,12) ,4) ) +transpose((transpose(X,-7) |transpose(X,4) ) ,7) ) ,-5) ,-7) ) +step((transpose(step(arpeggio(transpose(X,-7) ) ,12) ,-5) +transpose((((((shuffle(X) +transpose((X+transpose(X,-5) ) ,12) ) +transpose(X,-7) ) +transpose((step(X,12) +transpose(transpose(X,4) ,4) ) ,4) ) +transpose(transpose(transpose(X,-5) ,4) ,7) ) +transpose((((X|X) +(echo(X,4,6) +transpose(X,7) ) ) +X) ,12) ) ,7) ) ,12) ) ,4,6) ,12) ) ,4) ) ,-7) ,12) ) ,4) ) +transpose((echo(shuffle((transpose(step(transpose(step(echo(transpose((step(X,12) +transpose(X,-5) ) ,-7) ,4,6) ,12) ,-5) ,12) ,-5) +transpose((((((transpose(X,4) +transpose((X+transpose(X,12) ) ,7) ) +transpose(transpose(transpose(X,-7) ,-5) ,4) ) +transpose((transpose(arpeggio(transpose(X,-7) ) ,-7) +transpose(shuffle(X) ,7) ) ,4) ) +transpose(transpose(arpeggio(X) ,-7) ,7) ) +(echo((((((X+transpose(X,12) ) +transpose(echo(X,4,6) ,4) ) +transpose(transpose(X,-5) ,7) ) +arpeggio((shuffle(X) +transpose(step(X,12) ,12) ) ) ) +transpose(step(X,12) ,-5) ) ,4,6) +transpose((echo(transpose((X+transpose(X,7) ) ,-5) ,4,6) +(transpose(step(echo(shuffle(X) ,4,6) ,12) ,-7) |(((transpose(X,-7) +transpose(X,4) ) +transpose(step(arpeggio(X) ,12) ,7) ) +transpose((((X+transpose(X,12) ) |X) +arpeggio(X) ) ,12) ) ) ) ,12) ) ) ,7) ) ) ,4,6) +transpose(((arpeggio(transpose(transpose(transpose(shuffle(transpose(X,-5) ) ,-5) ,-7) ,-5) ) +transpose(step(transpose(transpose(transpose(shuffle(X) ,-5) ,-5) ,-5) ,12) ,12) ) +transpose(transpose(transpose((transpose((shuffle((X+transpose(X,7) ) ) +transpose(((X+transpose((X+transpose(X,12) ) ,12) ) |(X+transpose(X,7) ) ) ,7) ) ,4) +transpose(transpose(step((step(X,12) |shuffle((X+X) ) ) ,12) ,-5) ,12) ) ,-7) ,-5) ,12) ) ,-7) ) ,7) )
random seed used was 236953422

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