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:
(((transpose((((shuffle(shuffle(((transpose(shuffle(arpeggio(transpose(X,-5) ) ) ,4) +transpose((((step(((X+transpose(X,4) ) +transpose(X,7) ) ,12) +transpose(transpose((X+transpose(X,7) ) ,-7) ,7) ) +transpose(transpose(echo(X,4,6) ,-5) ,12) ) +transpose(transpose(transpose((X|X) ,-5) ,4) ,-5) ) ,4) ) +transpose((arpeggio(echo(transpose(((arpeggio(X) +transpose((X+transpose(X,7) ) ,7) ) +transpose(transpose(X,-5) ,7) ) ,-7) ,4,6) ) +transpose((((transpose(X,-5) +step((X|X) ,12) ) +transpose(arpeggio(((X+transpose(X,4) ) +transpose(X,7) ) ) ,4) ) +transpose(shuffle(arpeggio(echo(X,4,6) ) ) ,7) ) ,7) ) ,7) ) ) ) +transpose(((transpose((((transpose(X,-5) +echo((X+transpose(X,12) ) ,4,6) ) |step((X+transpose(X,7) ) ,12) ) +transpose(transpose(((transpose(X,-5) |X) |transpose(X,-7) ) ,-7) ,7) ) ,4) +transpose(transpose(((transpose(arpeggio((arpeggio(X) |(X+X) ) ) ,-7) +transpose(arpeggio(((transpose(transpose((X+transpose(X,12) ) ,4) ,4) +transpose(arpeggio((echo(X,4,6) +X) ) ,12) ) |echo(((X+transpose(X,4) ) +transpose(X,7) ) ,4,6) ) ) ,7) ) |shuffle(arpeggio(arpeggio((transpose(X,-5) |transpose((X|X) ,-7) ) ) ) ) ) ,-5) ,7) ) +transpose(transpose((((transpose(transpose(X,-7) ,4) +transpose(transpose(X,-7) ,4) ) +transpose(transpose((X|((echo(X,4,6) +transpose(transpose(X,-7) ,4) ) +transpose(shuffle(X) ,7) ) ) ,-5) ,7) ) +transpose((transpose(((echo(X,4,6) +transpose((X+transpose(X,12) ) ,12) ) |(transpose(X,-5) |X) ) ,-7) +transpose(transpose((shuffle((X+transpose((X+transpose(X,12) ) ,7) ) ) |(echo((X+transpose(X,7) ) ,4,6) |transpose(X,-7) ) ) ,-5) ,12) ) ,7) ) ,-7) ,12) ) ,4) ) +transpose(transpose(((((transpose(transpose(transpose(transpose(shuffle((X+X) ) ,-7) ,-7) ,-7) ,4) +transpose((((((X+transpose(X,7) ) +transpose((transpose(X,4) +X) ,4) ) +transpose((X+transpose(X,7) ) ,7) ) +transpose((shuffle(((X|X) +transpose((X|X) ,12) ) ) +(transpose((X|X) ,4) +transpose(echo(X,4,6) ,12) ) ) ,4) ) +transpose(transpose(((((X+X) |transpose(X,-5) ) +transpose(echo(X,4,6) ,4) ) +transpose((transpose(X,-7) +(X+transpose(X,7) ) ) ,7) ) ,4) ,7) ) ,4) ) +transpose((transpose(transpose((arpeggio(arpeggio(X) ) +((X+transpose(step(X,12) ,4) ) +transpose(X,7) ) ) ,-5) ,-7) +transpose(transpose(transpose((X+transpose(X,7) ) ,-5) ,-5) ,12) ) ,7) ) +transpose(transpose(((shuffle(transpose(X,-7) ) +transpose((X+transpose(X,12) ) ,12) ) +transpose((((X|X) |(X|X) ) |X) ,12) ) ,4) ,4) ) |transpose(transpose((echo(X,4,6) +transpose((X+(X+transpose(X,12) ) ) ,7) ) ,4) ,-7) ) ,-7) ,7) ) +shuffle(((arpeggio((shuffle((transpose(step((X|X) ,12) ,4) |((transpose(X,-5) +transpose(transpose(X,4) ,12) ) +transpose((X+transpose(X,7) ) ,12) ) ) ) |transpose(transpose((X+transpose(X,7) ) ,4) ,-5) ) ) +transpose(transpose(transpose(step(transpose((shuffle(X) +(arpeggio(step(X,12) ) +(X+X) ) ) ,4) ,12) ,4) ,4) ,12) ) +(echo(arpeggio(arpeggio(transpose(arpeggio(transpose(X,-7) ) ,-5) ) ) ,4,6) |transpose(((transpose(X,-7) +(X+X) ) +(transpose(echo((X+transpose(X,12) ) ,4,6) ,-5) |arpeggio((X|X) ) ) ) ,-5) ) ) ) ) ,-5) +transpose(arpeggio(transpose(((transpose(((shuffle(((X+transpose(transpose(X,-7) ,12) ) |(transpose(X,4) +transpose(transpose((X|X) ,-5) ,12) ) ) ) |echo(transpose(shuffle(transpose(X,-7) ) ,-5) ,4,6) ) +transpose((((((((((X+transpose(X,4) ) +transpose(X,7) ) |arpeggio(X) ) +transpose(X,4) ) +transpose(((transpose(X,4) +X) +transpose(X,12) ) ,4) ) +transpose(shuffle(((transpose(X,-5) +transpose((X|X) ,4) ) +transpose(X,7) ) ) ,7) ) +transpose(transpose(transpose(transpose(X,-7) ,4) ,-7) ,12) ) +transpose(arpeggio((shuffle(transpose(X,-5) ) +transpose(((shuffle(X) +transpose(transpose(transpose(X,-5) ,-5) ,4) ) +transpose(arpeggio(X) ,7) ) ,7) ) ) ,7) ) +(transpose((((X+transpose(X,12) ) |(X+transpose(X,12) ) ) |transpose(echo(X,4,6) ,-5) ) ,-5) +transpose(transpose((X|X) ,-7) ,-5) ) ) ,7) ) ,-5) +transpose(((echo(echo((transpose(((X+X) +transpose(shuffle((X+transpose(X,12) ) ) ,12) ) ,4) +(X+(((X+X) +transpose(echo(X,4,6) ,4) ) +transpose((X+transpose(X,12) ) ,7) ) ) ) ,4,6) ,4,6) +transpose(step(step(X,12) ,12) ,4) ) +transpose(transpose(transpose(transpose(((((X+echo(X,4,6) ) +transpose(transpose((transpose(X,4) |(X+X) ) ,4) ,12) ) +transpose((transpose((X+transpose(X,12) ) ,-5) +transpose((X+transpose(transpose(X,-7) ,7) ) ,7) ) ,12) ) +transpose((X+X) ,7) ) ,-5) ,-5) ,-5) ,7) ) ,-7) ) |transpose(((((((step((X+transpose(X,12) ) ,12) +transpose(transpose(step((X+transpose(X,12) ) ,12) ,4) ,4) ) +transpose(transpose(echo(echo(X,4,6) ,4,6) ,4) ,7) ) +transpose(shuffle(((X+transpose(X,4) ) +transpose(X,7) ) ) ,4) ) |transpose((transpose(X,-5) +X) ,-5) ) |transpose(shuffle(step((arpeggio(X) +((X+X) |X) ) ,12) ) ,4) ) +transpose(((transpose(shuffle(shuffle(((transpose(transpose(step(X,12) ,-5) ,-7) +transpose(transpose(X,-7) ,4) ) +transpose(transpose((X+transpose(transpose(X,-5) ,12) ) ,-7) ,7) ) ) ) ,4) +transpose(((echo(step((X+transpose(X,12) ) ,12) ,4,6) +transpose(shuffle(transpose(transpose(X,-5) ,4) ) ,7) ) +arpeggio(((arpeggio(transpose(X,-5) ) +arpeggio(X) ) |transpose(transpose((X|transpose(X,-7) ) ,4) ,-7) ) ) ) ,4) ) +transpose((transpose((((transpose((X+transpose(X,7) ) ,-7) |transpose(transpose(X,-5) ,4) ) +transpose(((X+X) |transpose(X,-5) ) ,12) ) +transpose(echo((transpose(transpose(step(X,12) ,4) ,4) +transpose((transpose(X,4) +transpose(X,12) ) ,12) ) ,4,6) ,7) ) ,-5) |shuffle(((X+((X|X) |X) ) |step(transpose(transpose(X,-7) ,-5) ,12) ) ) ) ,7) ) ,7) ) ,4) ) ,-7) ) ,12) ) +transpose(echo((transpose(((((transpose(transpose(transpose(((transpose(step(X,12) ,4) +transpose(transpose(X,-5) ,12) ) +transpose((transpose(((X+transpose(X,7) ) +transpose((X+transpose(X,12) ) ,12) ) ,4) |(transpose(((echo(X,4,6) +transpose(X,4) ) +transpose(arpeggio(X) ,7) ) ,4) +(X+((X+X) +transpose((X+transpose(X,7) ) ,7) ) ) ) ) ,12) ) ,4) ,-5) ,-5) +transpose(((shuffle((((((X+transpose(X,7) ) +X) +transpose(transpose(X,-5) ,4) ) +transpose(transpose(transpose(transpose(X,-5) ,-7) ,-7) ,12) ) +transpose((transpose(shuffle(step(X,12) ) ,4) +((echo((X|X) ,4,6) +transpose(X,4) ) +transpose(transpose(X,4) ,7) ) ) ,7) ) ) +transpose(step(step(arpeggio((shuffle(transpose(X,-7) ) +(transpose(X,-7) +transpose(transpose(X,4) ,-5) ) ) ) ,12) ,12) ,4) ) +transpose(((arpeggio(X) |step(transpose(echo(transpose(X,-5) ,4,6) ,4) ,12) ) +transpose(arpeggio(X) ,4) ) ,7) ) ,4) ) +transpose((transpose(transpose(transpose((((((X+transpose(X,4) ) +transpose(X,7) ) |X) +transpose(transpose((X|X) ,4) ,4) ) +transpose((transpose(X,-5) +transpose(X,7) ) ,7) ) ,-5) ,4) ,-7) +transpose((((((transpose(X,-7) +transpose((X|X) ,12) ) +step(X,12) ) |transpose(X,-7) ) |(((X+transpose(X,12) ) |(X|X) ) |X) ) +transpose(transpose((X+transpose(X,7) ) ,4) ,12) ) ,12) ) ,7) ) +transpose(transpose(arpeggio((shuffle(transpose(transpose(((X|X) |((X+transpose(X,4) ) +transpose(X,7) ) ) ,4) ,4) ) +transpose(transpose(transpose((X+transpose(X,12) ) ,-7) ,-5) ,-7) ) ) ,-7) ,4) ) +transpose(transpose(transpose((arpeggio((transpose(X,-5) +(X+transpose(X,-5) ) ) ) +transpose((shuffle((shuffle(X) +transpose((X+X) ,7) ) ) +transpose(transpose(X,-7) ,7) ) ,7) ) ,-7) ,-5) ,7) ) ,4) +transpose(((((transpose(step(X,12) ,-5) +transpose(echo(echo(((echo(((transpose((X+transpose(transpose(X,4) ,12) ) ,-5) +transpose(transpose(step(X,12) ,4) ,4) ) +transpose(echo(step((transpose(X,-5) +transpose((X+X) ,7) ) ,12) ,4,6) ,7) ) ,4,6) +transpose(transpose(transpose((transpose(transpose(X,4) ,-7) |shuffle(X) ) ,-5) ,4) ,4) ) +transpose(((((transpose(X,4) +transpose(X,4) ) +transpose(X,7) ) +transpose(((X|X) +transpose((X+transpose(arpeggio(X) ,12) ) ,7) ) ,7) ) +(step(((X+transpose(X,12) ) +(X+transpose(X,7) ) ) ,12) +transpose(transpose(X,-7) ,-7) ) ) ,7) ) ,4,6) ,4,6) ,-7) ) +transpose(((echo((((transpose((X+transpose(X,12) ) ,4) |(X|X) ) +transpose((((X+transpose(transpose(X,4) ,4) ) +transpose(X,7) ) +transpose(((step(X,12) +transpose(step(X,12) ,4) ) +transpose(X,7) ) ,4) ) ,7) ) +((((step(X,12) +transpose((X+transpose(X,12) ) ,12) ) +(X|(X|X) ) ) +transpose(((transpose(X,4) +transpose(((X+transpose(X,12) ) +transpose((transpose(X,-7) +transpose(arpeggio(X) ,12) ) ,12) ) ,4) ) +transpose(transpose(X,-5) ,7) ) ,4) ) +transpose(arpeggio(echo(transpose(X,-7) ,4,6) ) ,7) ) ) ,4,6) +transpose((step((step(shuffle((X+transpose(transpose(X,-7) ,12) ) ) ,12) |transpose(((X+transpose(X,12) ) +transpose(transpose((X+X) ,-5) ,12) ) ,-5) ) ,12) +transpose(echo((arpeggio(transpose(((X+transpose(X,7) ) |X) ,-5) ) +transpose(transpose(transpose(shuffle(X) ,-5) ,4) ,12) ) ,4,6) ,7) ) ,4) ) +transpose(echo(echo(transpose((transpose((X+X) ,-7) +(transpose(X,-5) +transpose(X,7) ) ) ,-7) ,4,6) ,4,6) ,7) ) ,12) ) +transpose((transpose(((((transpose((X+X) ,-7) +transpose(transpose(X,-5) ,-5) ) +transpose((X|X) ,7) ) |arpeggio((transpose(transpose(X,-7) ,-5) |((transpose(arpeggio(echo(X,4,6) ) ,-7) +transpose(transpose(X,4) ,4) ) +transpose(transpose(arpeggio((X+X) ) ,-5) ,7) ) ) ) ) +transpose(((transpose(arpeggio((X|X) ) ,4) |((transpose((X+((X+transpose(X,4) ) +transpose(X,7) ) ) ,4) +transpose(((transpose(shuffle(X) ,4) +transpose((X+(X+transpose(X,12) ) ) ,4) ) +transpose(((X+X) +(X|X) ) ,7) ) ,4) ) +transpose(step(((X+transpose(transpose(X,4) ,4) ) +transpose(X,7) ) ,12) ,7) ) ) +transpose(step((X+transpose(X,-5) ) ,12) ,12) ) ,-5) ) ,-7) +transpose((((transpose(transpose(((echo(X,4,6) +transpose(((X+X) +X) ,4) ) +transpose((X+transpose(X,4) ) ,7) ) ,4) ,-7) +transpose(step((transpose(X,4) |transpose((X+X) ,4) ) ,12) ,-5) ) +transpose((((arpeggio(shuffle(transpose(X,-7) ) ) +transpose(shuffle((transpose(transpose(X,4) ,4) +transpose((X|X) ,7) ) ) ,-5) ) +transpose(transpose(echo(echo((X|X) ,4,6) ,4,6) ,-5) ,7) ) +transpose(transpose(transpose(transpose(transpose(((X|X) |X) ,4) ,-7) ,4) ,-5) ,12) ) ,4) ) +transpose(shuffle(transpose(((transpose(((X+X) |transpose(X,-7) ) ,-7) |(X+transpose((X+transpose(X,12) ) ,7) ) ) |((step(transpose(X,4) ,12) +transpose((transpose(transpose((X+transpose(transpose(X,-5) ,7) ) ,-5) ,-5) +transpose((((X|X) +transpose(transpose(X,-7) ,4) ) +transpose(shuffle((transpose(X,-5) +transpose(X,12) ) ) ,7) ) ,7) ) ,4) ) +transpose(((transpose(X,-5) +transpose(transpose(X,4) ,-5) ) +transpose(transpose(transpose(step(X,12) ,4) ,-7) ,12) ) ,7) ) ) ,-5) ) ,7) ) ,7) ) ,7) ) +transpose(transpose((((transpose(step(transpose(transpose(transpose(transpose(shuffle(X) ,-5) ,-7) ,4) ,-7) ,12) ,-7) +transpose((step(((((((X+transpose(transpose(X,-7) ,12) ) +transpose(shuffle(X) ,4) ) +transpose((X|X) ,7) ) |transpose(transpose(X,-5) ,-7) ) +transpose(step(transpose((transpose(X,4) +transpose((X+transpose(X,12) ) ,12) ) ,4) ,12) ,4) ) +transpose(((X+X) |X) ,7) ) ,12) +transpose((((((X+X) +transpose(X,7) ) +transpose(transpose(X,-5) ,4) ) +transpose((X+transpose(X,12) ) ,7) ) +transpose(echo(arpeggio((X|X) ) ,4,6) ,-7) ) ,12) ) ,4) ) +transpose(transpose(shuffle((X|X) ) ,4) ,7) ) |echo((((((X+transpose(((transpose(X,-7) +transpose((X+X) ,4) ) +transpose((X|X) ,7) ) ,7) ) +(step(echo(transpose(X,4) ,4,6) ,12) +transpose((X|X) ,7) ) ) +transpose(shuffle((X+transpose(X,7) ) ) ,12) ) |(transpose(((transpose(X,-7) +transpose((X|X) ,7) ) +transpose((arpeggio(X) +transpose(X,4) ) ,-7) ) ,4) +transpose(((transpose(X,4) |transpose(X,-7) ) +transpose(transpose((echo(X,4,6) +(X+X) ) ,-5) ,12) ) ,12) ) ) +transpose((((transpose(X,4) +transpose(step(((X+transpose(X,4) ) +transpose(X,7) ) ,12) ,12) ) +transpose((echo((X+X) ,4,6) |((transpose(X,-5) +transpose((transpose((X+transpose(X,7) ) ,4) |(echo(X,4,6) |((X+transpose(X,7) ) +transpose(X,7) ) ) ) ,4) ) +transpose(transpose(transpose(X,-5) ,-7) ,7) ) ) ,4) ) +transpose(transpose((((transpose(X,4) +transpose(echo(echo(X,4,6) ,4,6) ,4) ) +transpose(X,7) ) |(transpose(X,-5) +transpose(((X+transpose(X,12) ) |X) ,7) ) ) ,-5) ,7) ) ,12) ) ,4,6) ) ,4) ,-5) ) ,12) ) ,4,6) ,4) ) +transpose(transpose(arpeggio(transpose(transpose(((((transpose((echo(((X+transpose(X,4) ) +transpose(X,7) ) ,4,6) |transpose((X+transpose(X,12) ) ,-7) ) ,-7) |(echo((arpeggio(shuffle(((X|X) |step((X+transpose(X,7) ) ,12) ) ) ) |(echo((X+transpose(X,12) ) ,4,6) |transpose(((transpose(X,4) |(X|X) ) |(shuffle(transpose(X,-7) ) +transpose(X,4) ) ) ,-7) ) ) ,4,6) +transpose(transpose(step(((((X+X) +transpose(echo(transpose(X,4) ,4,6) ,7) ) +transpose(step((X|X) ,12) ,12) ) |((((transpose(X,4) +transpose(transpose(X,-5) ,12) ) +transpose(X,7) ) +transpose(transpose(transpose((X|X) ,-5) ,4) ,7) ) +transpose(transpose(((step(shuffle(X) ,12) +transpose(X,4) ) +transpose(X,7) ) ,-5) ,12) ) ) ,12) ,4) ,7) ) ) +(transpose(arpeggio(shuffle(transpose((X|X) ,4) ) ) ,4) +arpeggio(transpose(echo(((echo(X,4,6) +transpose(echo(arpeggio(X) ,4,6) ,7) ) +step((X+transpose(transpose(X,-5) ,7) ) ,12) ) ,4,6) ,4) ) ) ) +transpose(echo(transpose(arpeggio(transpose(((((transpose(X,-5) +transpose(echo(X,4,6) ,7) ) +(transpose(X,-7) +transpose(X,7) ) ) +transpose(((transpose(X,-7) +echo(X,4,6) ) |transpose((X|(X+transpose(X,12) ) ) ,4) ) ,4) ) +transpose(transpose(((transpose(shuffle(X) ,4) +transpose(transpose(X,4) ,4) ) +transpose(arpeggio(X) ,7) ) ,-5) ,7) ) ,-5) ) ,-7) ,4,6) ,4) ) +transpose((((((((((transpose(transpose(shuffle(X) ,4) ,4) +transpose(step(transpose(X,4) ,12) ,4) ) +transpose(echo(arpeggio((((X|X) +transpose(X,12) ) +transpose((transpose(X,-7) +X) ,7) ) ) ,4,6) ,7) ) +transpose(step(((X+arpeggio(X) ) +step((X+X) ,12) ) ,12) ,12) ) +transpose(transpose(transpose((transpose((X+transpose(X,7) ) ,-5) +transpose((shuffle(transpose(X,-7) ) +transpose(arpeggio(X) ,4) ) ,7) ) ,-7) ,-5) ,4) ) +transpose((transpose((((((X+transpose(X,12) ) +transpose(step(X,12) ,4) ) +transpose(transpose(transpose(X,-7) ,-5) ,7) ) |transpose((X+transpose(X,12) ) ,-5) ) +transpose(step((((((X+transpose(X,7) ) +transpose(X,4) ) +transpose(X,7) ) +transpose((X+X) ,4) ) +transpose(((X|X) +arpeggio(X) ) ,7) ) ,12) ,12) ) ,-5) +transpose(transpose(((arpeggio((transpose(X,-5) +transpose((X|X) ,7) ) ) |arpeggio((X+transpose((X+transpose(X,12) ) ,12) ) ) ) +transpose(((shuffle(X) +transpose(((X+transpose(X,4) ) +transpose((X|X) ,7) ) ,4) ) +transpose(transpose(X,4) ,7) ) ,12) ) ,-5) ,12) ) ,7) ) +transpose(transpose(((step(((X+transpose(X,12) ) |shuffle((X|X) ) ) ,12) +transpose(echo(X,4,6) ,4) ) +transpose(shuffle(transpose(X,4) ) ,7) ) ,4) ,4) ) +transpose((transpose((transpose(arpeggio(X) ,-7) |(step(echo(X,4,6) ,12) +transpose((X+((X+transpose(X,4) ) +transpose((X+transpose(X,12) ) ,7) ) ) ,7) ) ) ,-7) +((((step(arpeggio(transpose(X,-5) ) ,12) |X) +transpose(echo(shuffle((X+transpose(X,7) ) ) ,4,6) ,4) ) +transpose(transpose(((transpose(X,-5) +transpose(X,12) ) |X) ,-5) ,7) ) +transpose((((transpose(X,-7) |transpose(echo(X,4,6) ,-5) ) +transpose(((X+transpose(X,7) ) +transpose(transpose(X,-5) ,4) ) ,4) ) +transpose(transpose(X,4) ,7) ) ,12) ) ) ,7) ) +transpose((transpose((transpose(((transpose(X,-7) +transpose(transpose(X,4) ,4) ) +transpose(echo(X,4,6) ,7) ) ,4) +(transpose((X+transpose(X,7) ) ,4) +((transpose(X,4) +transpose(shuffle(X) ,4) ) +transpose((X+transpose(X,7) ) ,7) ) ) ) ,-7) +transpose(transpose(transpose((X+X) ,4) ,-7) ,12) ) ,4) ) +transpose((((echo(X,4,6) +echo(transpose(shuffle(arpeggio(transpose(X,4) ) ) ,-5) ,4,6) ) +transpose(transpose(transpose(((shuffle(((X+transpose(X,4) ) +transpose(X,7) ) ) +transpose(step(((transpose(X,4) +transpose(transpose(arpeggio(X) ,-5) ,4) ) +transpose(X,7) ) ,12) ,4) ) +transpose((((shuffle(X) +transpose(shuffle((X|X) ) ,7) ) +transpose((X+step(X,12) ) ,4) ) +transpose(transpose(X,-7) ,7) ) ,7) ) ,-5) ,4) ,12) ) +transpose(((((X|X) +transpose(shuffle(X) ,12) ) +transpose(transpose(X,4) ,7) ) +transpose(transpose(((X+transpose(X,4) ) +transpose(X,7) ) ,-7) ,12) ) ,4) ) ,7) ) ,4) ) ,-7) ,-7) ) ,-7) ,7) )
random seed used was 257110772

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