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:
(step((transpose((((arpeggio(((transpose(shuffle((transpose(transpose(X,-7) ,-5) |(X+arpeggio(transpose(X,-7) ) ) ) ) ,-5) +transpose(transpose(arpeggio(transpose(echo(X,4,6) ,-5) ) ,-7) ,4) ) +transpose((transpose((((((shuffle(echo(X,4,6) ) +transpose(((X+transpose(X,7) ) |X) ,4) ) +transpose(((X|transpose(X,-7) ) +((X+transpose(X,7) ) +X) ) ,7) ) |transpose((step(X,12) |((X|X) |((X+transpose(X,12) ) +transpose(X,4) ) ) ) ,-5) ) +transpose(((transpose(transpose(transpose(X,-7) ,4) ,-5) +transpose((transpose(((X+transpose(X,12) ) +transpose(X,12) ) ,4) +transpose(transpose(transpose(X,4) ,-7) ,12) ) ,12) ) |transpose((transpose(X,-7) +transpose((X+transpose(X,12) ) ,7) ) ,-5) ) ,4) ) +transpose((((transpose((((X+X) +transpose(X,4) ) +transpose(X,7) ) ,-5) +transpose((arpeggio(X) +transpose(transpose(X,-7) ,7) ) ,7) ) +transpose(transpose(((X|X) +echo(X,4,6) ) ,-7) ,4) ) +transpose((echo(step(X,12) ,4,6) +transpose((transpose(step(X,12) ,4) |transpose(step((X|X) ,12) ,-7) ) ,7) ) ,7) ) ,7) ) ,4) |transpose(transpose((((X+X) +transpose(X,12) ) +transpose(X,12) ) ,-7) ,-5) ) ,7) ) ) +transpose(transpose((((((transpose(transpose(X,-5) ,4) +transpose((transpose((X|X) ,4) +X) ,12) ) |transpose(transpose(X,4) ,4) ) +transpose(step(arpeggio(((X+X) +(transpose(X,4) +X) ) ) ,12) ,4) ) +transpose(transpose(X,-7) ,7) ) +transpose(((transpose(arpeggio(transpose(step(X,12) ,-7) ) ,4) +transpose(echo(echo(X,4,6) ,4,6) ,4) ) +transpose((((transpose(((X+X) |transpose(X,-7) ) ,4) +transpose(transpose(shuffle(X) ,4) ,4) ) +transpose((shuffle(X) +transpose(((X+transpose(X,4) ) +transpose(X,7) ) ,12) ) ,7) ) +transpose(step((X+X) ,12) ,-7) ) ,7) ) ,12) ) ,-5) ,4) ) +transpose(((((echo((((X|transpose(X,-7) ) |((X+transpose(((X+transpose(X,4) ) +transpose(X,7) ) ,12) ) +transpose(X,12) ) ) |transpose((((X+transpose(X,-5) ) +transpose(transpose(transpose(X,-7) ,4) ,4) ) +transpose((X+(echo(X,4,6) +transpose(X,-7) ) ) ,7) ) ,-7) ) ,4,6) +transpose(step(echo((transpose((transpose(X,4) +transpose(transpose(X,-5) ,12) ) ,-5) +transpose(((X+transpose(transpose(X,-5) ,4) ) +transpose(((X+transpose(X,4) ) +transpose(X,7) ) ,7) ) ,7) ) ,4,6) ,12) ,7) ) |transpose(transpose(echo(step((transpose(X,-7) |X) ,12) ,4,6) ,-7) ,-7) ) |step(((transpose((transpose((X+transpose(X,4) ) ,-7) +transpose((step(transpose(X,4) ,12) +transpose(X,-5) ) ,12) ) ,4) |(arpeggio(transpose((transpose(X,-7) +transpose(X,7) ) ,-7) ) +(((X+transpose(X,4) ) +transpose(X,7) ) +transpose((((X+X) +transpose((X+transpose(X,7) ) ,12) ) |((X+transpose(X,12) ) |X) ) ,7) ) ) ) |step(transpose((step(X,12) +transpose(transpose(X,-7) ,7) ) ,-7) ,12) ) ,12) ) |transpose(transpose(transpose(transpose(X,-7) ,-5) ,-5) ,4) ) ,7) ) +(transpose((step(shuffle(((X+X) +transpose(X,12) ) ) ,12) +(transpose((transpose((X+X) ,4) +transpose(transpose(transpose(arpeggio(X) ,4) ,-7) ,12) ) ,-5) |transpose(transpose(transpose(X,-5) ,4) ,-5) ) ) ,-7) |transpose(transpose(arpeggio((X+transpose(arpeggio(X) ,12) ) ) ,-7) ,-7) ) ) ,4) +transpose(shuffle(transpose(((transpose((((echo((transpose(X,4) +transpose(((X+X) +transpose(transpose(X,4) ,12) ) ,7) ) ,4,6) +(echo(transpose(transpose((X+X) ,-7) ,4) ,4,6) +transpose(echo((step(transpose(X,-5) ,12) +transpose((((X+transpose(X,12) ) +(X+transpose(X,7) ) ) +transpose(transpose(X,-5) ,12) ) ,7) ) ,4,6) ,12) ) ) +transpose(transpose(transpose((((arpeggio((echo(transpose(X,-7) ,4,6) |shuffle((X+transpose(X,7) ) ) ) ) +transpose(X,4) ) +transpose(transpose(X,-7) ,7) ) +transpose(transpose(arpeggio(arpeggio(X) ) ,4) ,12) ) ,-7) ,-7) ,12) ) +transpose(transpose(transpose(((X+(X+transpose(X,12) ) ) |transpose((transpose(transpose(X,-5) ,-7) +transpose(X,12) ) ,-5) ) ,-5) ,-5) ,7) ) ,4) +transpose(transpose(echo(transpose(transpose(((transpose(X,-7) +transpose(((X+transpose(X,4) ) +transpose(X,7) ) ,4) ) +transpose(X,7) ) ,-5) ,-5) ,4,6) ,-7) ,4) ) +transpose((transpose((transpose(((X+X) +(X+X) ) ,-7) +((((shuffle(arpeggio(X) ) +arpeggio(X) ) +transpose(((shuffle((X+(X|X) ) ) +transpose(X,4) ) +transpose(transpose((X+transpose(X,-7) ) ,-5) ,12) ) ,4) ) +transpose(shuffle(((X+transpose(X,4) ) +transpose(X,7) ) ) ,7) ) |arpeggio(echo(transpose((transpose(arpeggio(X) ,-7) |transpose(X,-7) ) ,4) ,4,6) ) ) ) ,-7) +((step(transpose(((arpeggio((X+X) ) +transpose(transpose(X,-7) ,4) ) +transpose((X+transpose(transpose(X,-5) ,12) ) ,7) ) ,-7) ,12) +transpose(transpose((X+transpose(X,7) ) ,4) ,12) ) +transpose((((((transpose(X,4) +shuffle(X) ) +transpose((transpose(X,4) +X) ,7) ) +((X+X) +((transpose(echo(X,4,6) ,-7) +transpose(echo(X,4,6) ,4) ) +transpose(echo(transpose((X+transpose(X,7) ) ,4) ,4,6) ,7) ) ) ) +transpose(((transpose(((X+X) |(X+echo(X,4,6) ) ) ,-5) +(echo(X,4,6) +X) ) +transpose(transpose((step(step(arpeggio((X+transpose(X,12) ) ) ,12) ,12) +(transpose(X,-5) |transpose(transpose((X+transpose(X,7) ) ,-7) ,-7) ) ) ,4) ,12) ) ,7) ) +transpose(shuffle(((transpose(step(((((X+transpose(X,4) ) +transpose(X,7) ) +transpose(X,4) ) +transpose((X+transpose(X,12) ) ,7) ) ,12) ,-7) +transpose(transpose((X+transpose(transpose(X,4) ,12) ) ,-7) ,12) ) |(transpose(((X+transpose(X,4) ) +transpose(X,7) ) ,4) +arpeggio(((X+transpose(X,4) ) +transpose(X,7) ) ) ) ) ) ,7) ) ,7) ) ) ,7) ) ,-5) ) ,12) ) ,12) +((step(transpose(transpose(((((transpose(step((transpose(step(transpose(X,4) ,12) ,-7) +transpose(transpose(transpose(transpose(X,-5) ,-7) ,4) ,7) ) ,12) ,-5) +transpose(transpose((transpose(transpose(X,4) ,-5) +(transpose(shuffle(((X+transpose(X,12) ) +transpose(X,7) ) ) ,-5) |transpose((((transpose(X,-5) |transpose(X,4) ) +transpose(transpose((X+X) ,-5) ,4) ) +transpose(arpeggio((X+X) ) ,7) ) ,4) ) ) ,-5) ,4) ) +transpose((((shuffle(echo((transpose((X+transpose(X,12) ) ,-5) +transpose(((((X+transpose(X,4) ) +transpose(X,7) ) |shuffle(X) ) +(transpose(X,4) +transpose(transpose(X,4) ,12) ) ) ,7) ) ,4,6) ) |((X+X) +transpose(transpose(shuffle((X+X) ) ,4) ,-5) ) ) +transpose((echo((((((X|X) +transpose(step(X,12) ,7) ) +transpose((transpose(X,4) |shuffle(X) ) ,4) ) +transpose((X+transpose(X,-5) ) ,7) ) +(((X+X) +transpose(X,12) ) +transpose((X|X) ,4) ) ) ,4,6) +transpose((transpose((X+transpose(X,12) ) ,-7) |(transpose((X+X) ,4) +echo(X,4,6) ) ) ,12) ) ,4) ) +transpose(transpose(transpose((transpose((X+X) ,-7) +transpose((echo(echo(X,4,6) ,4,6) |arpeggio(((X+transpose(X,4) ) +transpose(X,7) ) ) ) ,12) ) ,-7) ,4) ,7) ) ,7) ) |echo((transpose(((((transpose(X,-5) +transpose((arpeggio(X) +transpose(X,12) ) ,12) ) +transpose((arpeggio(X) +transpose(X,12) ) ,4) ) +transpose((X+transpose((X|X) ,7) ) ,7) ) +shuffle((X|(X+transpose(X,12) ) ) ) ) ,-7) +arpeggio(echo((((X|X) |X) +transpose(step(echo(X,4,6) ,12) ,12) ) ,4,6) ) ) ,4,6) ) +shuffle(step(echo((transpose((((X+transpose(X,7) ) +transpose(X,-7) ) +((X+X) +transpose((X|X) ,7) ) ) ,-5) +echo(((transpose(X,4) |X) +(shuffle(X) +transpose((X|X) ,12) ) ) ,4,6) ) ,4,6) ,12) ) ) ,-7) ,-5) ,12) |(arpeggio(((((shuffle((((((transpose(X,-7) +transpose(shuffle(X) ,7) ) |X) +transpose(transpose(X,-5) ,12) ) +transpose(((X+transpose(X,12) ) +transpose(((X+transpose((X+X) ,4) ) +transpose((X|X) ,7) ) ,12) ) ,7) ) +(transpose(transpose(echo((((X+transpose(X,7) ) +transpose(arpeggio(X) ,4) ) +transpose(X,7) ) ,4,6) ,-5) ,-5) |(transpose((shuffle(X) +transpose(shuffle(echo(X,4,6) ) ,12) ) ,4) |shuffle((((X+transpose(X,12) ) |transpose(X,-5) ) +transpose(transpose((X+X) ,-7) ,7) ) ) ) ) ) ) +transpose((((transpose((echo(X,4,6) |X) ,-5) |(X+transpose(X,7) ) ) +transpose((transpose((transpose((X+X) ,-7) +transpose((X+transpose((X+transpose(X,7) ) ,12) ) ,7) ) ,4) +transpose(((transpose(transpose(X,-5) ,-7) +transpose((transpose(X,-7) |(transpose(X,4) |transpose(X,-5) ) ) ,4) ) +transpose(echo(transpose(X,-7) ,4,6) ,7) ) ,7) ) ,4) ) +transpose(transpose(transpose((X+X) ,-7) ,-5) ,7) ) ,7) ) |(transpose((step((shuffle((transpose(X,4) +transpose(transpose(X,4) ,12) ) ) +transpose(transpose((transpose(X,4) |((X+transpose(X,7) ) +transpose(transpose(X,-5) ,7) ) ) ,-7) ,7) ) ,12) |transpose(transpose((step(transpose(X,4) ,12) +echo((((X+transpose(step(X,12) ,4) ) +transpose((X|X) ,7) ) +transpose(X,-5) ) ,4,6) ) ,-5) ,-7) ) ,-5) +transpose((transpose((transpose((transpose(step(X,12) ,-7) |transpose(shuffle(shuffle(X) ) ,-5) ) ,-7) |echo(((X+transpose(echo(X,4,6) ,7) ) +transpose((X+transpose(X,12) ) ,4) ) ,4,6) ) ,4) |(shuffle(step(X,12) ) +transpose(transpose(((X+transpose(X,4) ) +transpose(X,7) ) ,-7) ,-5) ) ) ,7) ) ) +transpose((transpose(shuffle(((transpose(X,-7) |transpose((transpose(X,-7) +transpose(X,7) ) ,4) ) +transpose((step((X+transpose(X,7) ) ,12) +transpose(transpose(X,4) ,12) ) ,12) ) ) ,4) +transpose((((transpose(transpose(transpose(X,-7) ,-7) ,-7) +transpose(transpose(transpose(transpose((X+transpose(echo((X|X) ,4,6) ,7) ) ,-7) ,-5) ,-5) ,4) ) +transpose(transpose((X+transpose(X,12) ) ,-7) ,7) ) +transpose((step(X,12) +transpose((((X|X) +transpose(transpose(transpose(X,4) ,4) ,4) ) +transpose(transpose(X,4) ,7) ) ,7) ) ,4) ) ,12) ) ,4) ) +transpose(step(transpose((transpose((arpeggio(echo(X,4,6) ) +transpose((X|X) ,-7) ) ,4) |(((X|(X+transpose(X,7) ) ) +X) |step((X+transpose(X,7) ) ,12) ) ) ,-5) ,12) ,7) ) ) +step((((((transpose(arpeggio(echo(step(((X+transpose(X,4) ) +transpose(X,7) ) ,12) ,4,6) ) ,4) +transpose((arpeggio(echo(transpose(X,-5) ,4,6) ) |((((X+transpose(X,12) ) +(X+transpose(X,7) ) ) +transpose((((X+echo(X,4,6) ) +transpose(X,4) ) +transpose(X,7) ) ,12) ) |step(shuffle(step(X,12) ) ,12) ) ) ,12) ) +transpose(shuffle(transpose(transpose(step((echo(X,4,6) +transpose(transpose(X,-5) ,12) ) ,12) ,-5) ,4) ) ,4) ) +transpose(((echo(transpose(((X+transpose(X,4) ) +transpose(X,7) ) ,-5) ,4,6) |(((transpose(transpose(X,-7) ,4) +transpose(transpose((transpose(X,-7) +transpose((X|X) ,12) ) ,4) ,12) ) +((step(X,12) +transpose(transpose(X,4) ,7) ) +transpose(arpeggio(arpeggio(step(X,12) ) ) ,12) ) ) +transpose(transpose((X+transpose(X,4) ) ,-7) ,7) ) ) +transpose((transpose(X,-5) +transpose(shuffle(((((X+transpose(X,4) ) +transpose(X,7) ) +transpose(transpose(X,-7) ,7) ) |arpeggio((transpose(X,4) +X) ) ) ) ,7) ) ,12) ) ,7) ) +transpose(((((((transpose(X,-5) +transpose((X+transpose(X,7) ) ,4) ) +transpose(X,7) ) +((((X+transpose(X,7) ) +transpose(transpose(X,4) ,7) ) +transpose(((X|X) +transpose(X,-7) ) ,4) ) +transpose((echo(X,4,6) +transpose(X,7) ) ,7) ) ) +((X|transpose(X,4) ) |transpose(X,4) ) ) +transpose(transpose((step(((X|X) +X) ,12) |shuffle(X) ) ,-5) ,7) ) |transpose((((((X+transpose(X,7) ) +transpose((X+transpose(X,12) ) ,4) ) +transpose(shuffle(X) ,7) ) +transpose(transpose((X+transpose(X,12) ) ,-7) ,7) ) |transpose(shuffle(echo(((X+X) +transpose(X,12) ) ,4,6) ) ,-5) ) ,-7) ) ,7) ) +transpose(arpeggio(((X|transpose(X,-7) ) +transpose(((X+transpose(X,12) ) |step(arpeggio(X) ,12) ) ,-7) ) ) ,7) ) ,12) ) ) +transpose((transpose(arpeggio(transpose(((shuffle((((transpose(step((X+transpose(X,12) ) ,12) ,-5) +transpose(transpose((transpose(transpose(transpose(X,4) ,4) ,-5) +transpose(((transpose(X,-7) |shuffle(X) ) +transpose(X,-5) ) ,7) ) ,-5) ,4) ) +transpose(shuffle(X) ,7) ) +transpose(arpeggio((((step((transpose(X,-5) +transpose(X,-5) ) ,12) +transpose(transpose(((echo(X,4,6) +transpose(X,4) ) +transpose(step(X,12) ,7) ) ,-7) ,7) ) +transpose((arpeggio(X) |(X+transpose(X,12) ) ) ,4) ) +transpose((transpose((transpose(X,-5) +transpose(X,-5) ) ,-7) |(X|X) ) ,7) ) ) ,12) ) ) |(transpose(arpeggio((transpose(X,-5) +transpose((X+transpose(X,7) ) ,7) ) ) ,-7) |transpose((echo(transpose(X,-5) ,4,6) +transpose(X,-5) ) ,-7) ) ) +transpose(((transpose(transpose((arpeggio(((X|X) +transpose((transpose(X,4) |transpose(X,-7) ) ,7) ) ) |step(step(transpose(X,4) ,12) ,12) ) ,-5) ,4) |((echo(shuffle(step((X+transpose(X,7) ) ,12) ) ,4,6) +transpose(transpose((transpose(echo(X,4,6) ,-7) +transpose((X+transpose(X,12) ) ,7) ) ,4) ,4) ) |((((X|X) +transpose((X+transpose(step(X,12) ,7) ) ,12) ) +transpose(((X|(X+X) ) +transpose(X,4) ) ,12) ) |(((X|(X|X) ) +(X+X) ) +(X|step(X,12) ) ) ) ) ) +transpose(transpose(((((step(((shuffle(X) +X) +transpose(((X+transpose(X,4) ) +transpose(X,7) ) ,12) ) ,12) +((X+X) +(X+step(X,12) ) ) ) +transpose((echo(X,4,6) |transpose((((X+transpose(shuffle(X) ,7) ) +transpose(transpose(X,4) ,4) ) +transpose(transpose(X,4) ,7) ) ,4) ) ,7) ) +transpose(transpose(transpose(transpose(echo(X,4,6) ,-7) ,-7) ,-5) ,4) ) +transpose(transpose(echo(transpose(((transpose(X,-7) |X) +shuffle((X+transpose(X,12) ) ) ) ,4) ,4,6) ,4) ,7) ) ,4) ,12) ) ,-5) ) ,-5) ) ,-7) +transpose(transpose(transpose(arpeggio(transpose((step(transpose((echo(transpose(transpose(X,-5) ,4) ,4,6) +transpose(((transpose(((X+transpose(X,4) ) +transpose(X,7) ) ,4) +((X+transpose(X,4) ) +transpose(X,7) ) ) +transpose((echo(X,4,6) +transpose((((X+transpose(X,4) ) +transpose(X,7) ) |transpose(X,4) ) ,7) ) ,12) ) ,7) ) ,4) ,12) +transpose(((((transpose(((arpeggio(arpeggio(transpose(X,-7) ) ) +transpose((transpose((X+transpose((X+X) ,12) ) ,-5) |(echo(transpose(X,-5) ,4,6) +transpose((X+X) ,12) ) ) ,4) ) +transpose(((((transpose(X,4) +transpose(transpose(step(X,12) ,4) ,7) ) +transpose(((X|X) +transpose((X+transpose(X,12) ) ,4) ) ,4) ) +transpose(echo((X+X) ,4,6) ,7) ) +transpose((X+transpose((X+X) ,7) ) ,-5) ) ,7) ) ,-7) |((transpose((X+X) ,-7) +transpose(echo((X+X) ,4,6) ,-5) ) |step(step((X+arpeggio(X) ) ,12) ,12) ) ) +transpose(((step((X+transpose((X|X) ,7) ) ,12) +transpose((arpeggio(((X+transpose((X|X) ,4) ) +transpose(X,7) ) ) +arpeggio(((X+transpose(X,7) ) +transpose((X|X) ,12) ) ) ) ,12) ) +transpose(step((((X+transpose(X,7) ) +transpose(transpose(arpeggio(X) ,-7) ,4) ) +transpose(arpeggio(echo((X+transpose(X,12) ) ,4,6) ) ,7) ) ,12) ,7) ) ,12) ) |((echo((shuffle(X) |X) ,4,6) +step(transpose(X,4) ,12) ) +(step(transpose(transpose(transpose(transpose(X,-5) ,-5) ,4) ,4) ,12) +(transpose((X+X) ,-5) +((step((X+X) ,12) +transpose(transpose(((X+transpose(X,4) ) +transpose(X,7) ) ,4) ,4) ) +transpose(transpose((arpeggio((X+X) ) |(X+transpose(X,7) ) ) ,-5) ,7) ) ) ) ) ) |shuffle(((transpose(transpose(transpose(X,-5) ,4) ,-5) |(echo(((transpose(X,4) +transpose(X,4) ) +transpose(transpose(X,-5) ,7) ) ,4,6) |arpeggio(transpose(X,-7) ) ) ) |(shuffle(X) +transpose(echo(((X|X) +(X+transpose(X,12) ) ) ,4,6) ,12) ) ) ) ) ,12) ) ,-5) ) ,-7) ,-5) ,7) ) ,7) ) )
random seed used was 237722881

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