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 18 generations the expression "X" became this:
(transpose((transpose(transpose(transpose(((transpose(((((X+transpose(X,12) ) +transpose(X,7) ) +transpose(arpeggio(echo(X,4,6) ) ,7) ) +(((step(X,12) +transpose((X|X) ,7) ) +transpose(transpose(transpose(transpose(X,4) ,-7) ,-7) ,4) ) +transpose(echo(transpose(step(step(X,12) ,12) ,-7) ,4,6) ,7) ) ) ,-7) |shuffle(step(echo(arpeggio((echo(X,4,6) +transpose(X,-5) ) ) ,4,6) ,12) ) ) +transpose(transpose(transpose(shuffle(arpeggio(arpeggio(X) ) ) ,-7) ,-7) ,12) ) ,-5) ,4) ,-5) +transpose(echo(transpose(transpose((((transpose(echo((((X+(X+transpose(X,7) ) ) +transpose(echo(X,4,6) ,4) ) +transpose(transpose(X,4) ,7) ) ,4,6) ,-5) +transpose(shuffle((transpose(step((((X+transpose(X,4) ) +transpose(X,7) ) +transpose(X,7) ) ,12) ,-5) +transpose(transpose(step(X,12) ,-7) ,12) ) ) ,12) ) +((shuffle((step(step(X,12) ,12) |(transpose(echo(X,4,6) ,-5) +step(arpeggio(X) ,12) ) ) ) +transpose(transpose(transpose(arpeggio(X) ,4) ,-7) ,4) ) +transpose(transpose(((((X+transpose(X,7) ) |X) +transpose(X,4) ) +transpose(X,7) ) ,-7) ,7) ) ) |step((((echo(step(X,12) ,4,6) +(transpose((X+transpose(X,12) ) ,-5) +transpose(step(X,12) ,7) ) ) +transpose((step(shuffle((X|X) ) ,12) |((X+transpose(transpose(((X+transpose(X,4) ) +transpose(X,7) ) ,-5) ,4) ) +transpose((X+transpose(X,12) ) ,7) ) ) ,7) ) |((transpose(shuffle(X) ,-5) +transpose((((transpose(arpeggio(X) ,-7) +transpose(((X|(X+X) ) +transpose((X+X) ,-7) ) ,12) ) +transpose(transpose(X,4) ,4) ) +transpose(transpose(arpeggio(X) ,4) ,7) ) ,4) ) +transpose(transpose(transpose(transpose(transpose(X,-5) ,-7) ,-7) ,-5) ,7) ) ) ,12) ) ,4) ,-5) ,4,6) ,12) ) ,-7) +transpose(shuffle((transpose((arpeggio(transpose((echo(transpose((X+transpose(X,12) ) ,4) ,4,6) +transpose((echo(arpeggio(transpose(X,-7) ) ,4,6) |transpose(transpose(((X+X) +transpose(transpose(X,-5) ,12) ) ,-5) ,-7) ) ,7) ) ,-7) ) |(transpose(transpose(transpose(shuffle(shuffle(X) ) ,4) ,-5) ,-7) +transpose(arpeggio((arpeggio(((shuffle(X) +transpose(step(((X+transpose(X,4) ) +transpose(X,7) ) ,12) ,12) ) +transpose(transpose(transpose(step(X,12) ,-7) ,-5) ,7) ) ) +transpose(((transpose(X,-7) +(transpose(X,-7) +transpose(X,12) ) ) +transpose(arpeggio(transpose((X+transpose(X,7) ) ,-5) ) ,12) ) ,7) ) ) ,12) ) ) ,-5) +step(shuffle((((transpose(step(shuffle((X+transpose(X,12) ) ) ,12) ,-5) +transpose(transpose(transpose((X+X) ,-7) ,-5) ,7) ) +transpose((step((transpose(transpose((X+transpose(X,12) ) ,-5) ,4) +transpose(arpeggio(X) ,12) ) ,12) +transpose(transpose(step((((X+transpose((X+transpose(X,12) ) ,12) ) +transpose(transpose((X+transpose(X,12) ) ,-7) ,4) ) +transpose(X,7) ) ,12) ,-5) ,12) ) ,4) ) +transpose(shuffle((((step(arpeggio(X) ,12) +transpose((transpose(X,-7) +echo(X,4,6) ) ,12) ) +transpose((((transpose((X+X) ,4) +transpose(transpose(step(X,12) ,-5) ,7) ) +transpose(shuffle(X) ,12) ) +transpose(((X+transpose(X,12) ) |transpose(X,-5) ) ,12) ) ,4) ) +transpose((arpeggio((X+transpose(transpose(X,-7) ,7) ) ) +transpose((transpose(transpose(X,-7) ,-5) +transpose(step(transpose((X+X) ,-7) ,12) ,7) ) ,12) ) ,7) ) ) ,7) ) ) ,12) ) ) ,12) )
random seed used was 209388457 EXPR = ((arpeggio((((echo((echo(shuffle(arpeggio((X+transpose(((X+transpose(X,4) ) +transpose(X,7) ) ,12) ) ) ) ,4,6) +transpose(shuffle(((transpose(X,-5) +transpose(X,4) ) +transpose(((transpose(X,-5) +transpose((X|X) ,4) ) +transpose(transpose(arpeggio(X) ,-7) ,7) ) ,7) ) ) ,12) ) ,4,6) +transpose((transpose(step((X+transpose(X,7) ) ,12) ,-7) +arpeggio(step(step(transpose(X,4) ,12) ,12) ) ) ,4) ) +transpose((echo(arpeggio(transpose(transpose(((step((step(step(X,12) ,12) +transpose((step(arpeggio((X+X) ) ,12) |step(shuffle(X) ,12) ) ,12) ) ,12) +transpose(((((X+transpose(X,12) ) +transpose(transpose(X,4) ,12) ) +transpose(transpose(transpose(X,-5) ,-7) ,7) ) +transpose((X+echo(X,4,6) ) ,7) ) ,4) ) +transpose(transpose(((X+transpose(X,-5) ) +transpose(X,12) ) ,-5) ,7) ) ,-7) ,-5) ) ,4,6) +transpose(arpeggio(shuffle(arpeggio((shuffle(arpeggio(step(arpeggio(X) ,12) ) ) +transpose((echo(transpose(transpose(echo(transpose(X,-5) ,4,6) ,4) ,4) ,4,6) +transpose(((step(X,12) +X) +transpose(transpose(((X+transpose(X,7) ) +transpose(step(X,12) ,12) ) ,-7) ,12) ) ,7) ) ,7) ) ) ) ) ,7) ) ,7) ) +transpose(transpose((arpeggio((echo((shuffle(transpose(transpose(transpose(transpose(transpose(transpose(X,4) ,4) ,-5) ,-7) ,-5) ,-7) ) +transpose((((transpose(X,-7) +transpose(X,12) ) +transpose((X+transpose(X,12) ) ,12) ) |(((((X+transpose(X,4) ) +transpose(X,7) ) +transpose(X,12) ) +transpose(X,4) ) +transpose(((X+transpose(((X+transpose(X,4) ) +transpose(X,7) ) ,4) ) +transpose(X,7) ) ,7) ) ) ,-7) ) ,4,6) +((step(arpeggio(transpose(X,-7) ) ,12) +transpose(((transpose(arpeggio((step(X,12) +transpose((X+transpose(echo(X,4,6) ,7) ) ,7) ) ) ,-7) +transpose((((arpeggio(X) +transpose(X,12) ) +transpose(((X|X) +transpose((X+transpose(X,12) ) ,12) ) ,4) ) +transpose(step(((X+transpose(X,4) ) +transpose(X,7) ) ,12) ,7) ) ,4) ) +transpose((transpose(((X+transpose(X,4) ) +transpose(X,7) ) ,-5) +transpose((transpose((X+X) ,-7) +transpose(arpeggio((X+X) ) ,12) ) ,12) ) ,7) ) ,4) ) +transpose(transpose(transpose(step(transpose(arpeggio(arpeggio(X) ) ,-7) ,12) ,-5) ,-7) ,7) ) ) ) +transpose(transpose(transpose(((arpeggio(X) +transpose((transpose(X,-5) +transpose(transpose(X,-5) ,12) ) ,12) ) +transpose(((transpose(X,-5) +transpose(X,4) ) +transpose(transpose(X,4) ,7) ) ,7) ) ,-7) ,-5) ,7) ) ,-5) ,12) ) ) +transpose(transpose(((echo(transpose(((arpeggio(transpose(X,-5) ) +transpose(((shuffle(X) +transpose(step(X,12) ,4) ) +transpose((transpose(X,-5) +transpose(X,12) ) ,7) ) ,4) ) +transpose(step((X+transpose(X,7) ) ,12) ,7) ) ,-7) ,4,6) |(((echo(X,4,6) +transpose(echo((X+X) ,4,6) ,7) ) +transpose((((X+transpose(X,4) ) +transpose(X,7) ) +transpose(((((echo(X,4,6) +transpose(X,4) ) +transpose(step(X,12) ,7) ) +transpose(shuffle(X) ,4) ) +transpose(transpose(transpose(transpose(X,-5) ,-5) ,4) ,7) ) ,12) ) ,7) ) |arpeggio(step(transpose((transpose(X,-5) |(X+transpose(transpose(X,4) ,7) ) ) ,-7) ,12) ) ) ) +transpose(transpose(shuffle(transpose(transpose(transpose(transpose(arpeggio(((transpose(X,-7) +transpose(transpose((X|X) ,-7) ,12) ) +transpose((transpose(transpose(X,4) ,-7) +transpose(step(X,12) ,7) ) ,7) ) ) ,4) ,-7) ,4) ,-5) ) ,-7) ,12) ) ,-5) ,4) ) +transpose(transpose(echo(arpeggio((echo(step(((arpeggio(echo(shuffle((transpose(X,-7) +transpose(echo((X+transpose(X,12) ) ,4,6) ,12) ) ) ,4,6) ) +transpose(transpose((((arpeggio((transpose(X,-5) +transpose(((echo(X,4,6) +transpose(X,4) ) +transpose((X+transpose(X,7) ) ,7) ) ,12) ) ) +transpose(transpose(step((step((X|X) ,12) +X) ,12) ,4) ,4) ) +transpose(shuffle((arpeggio(X) +transpose(transpose(X,-5) ,7) ) ) ,7) ) +transpose(transpose((transpose(transpose(X,-5) ,-7) +transpose(X,-5) ) ,-7) ,7) ) ,-7) ,4) ) +transpose(step((((X+transpose(X,7) ) +transpose((X+transpose(transpose(X,4) ,7) ) ,12) ) +transpose(transpose(step(X,12) ,-7) ,7) ) ,12) ,7) ) ,12) ,4,6) +transpose(step((((((transpose(X,-5) +transpose((X+transpose(transpose(X,-5) ,12) ) ,7) ) +transpose(shuffle(shuffle((transpose(X,-7) |shuffle(X) ) ) ) ,7) ) +transpose(transpose(step(arpeggio((X+transpose(step((X+transpose(X,7) ) ,12) ,7) ) ) ,12) ,-5) ,12) ) +transpose(transpose(transpose((((arpeggio(transpose(X,4) ) +transpose(shuffle(transpose(X,-7) ) ,7) ) |((arpeggio(X) +transpose(echo((X+X) ,4,6) ,4) ) +transpose((X+X) ,7) ) ) +transpose(shuffle((echo((X+transpose(X,12) ) ,4,6) +transpose((((X+transpose(X,12) ) +transpose(((X+transpose(X,4) ) +transpose(X,7) ) ,4) ) +transpose((X+transpose(X,12) ) ,7) ) ,12) ) ) ,7) ) ,-5) ,-7) ,4) ) +transpose(transpose((transpose((transpose(transpose(echo(X,4,6) ,4) ,-7) |(arpeggio(arpeggio(transpose(X,-7) ) ) +transpose(step(X,12) ,7) ) ) ,4) +transpose(((transpose(((X+transpose(transpose(X,4) ,7) ) +transpose(transpose((echo((X+X) ,4,6) +transpose(transpose(X,-5) ,12) ) ,-5) ,12) ) ,-7) +transpose(shuffle((step(X,12) +transpose(X,12) ) ) ,4) ) +transpose(shuffle(transpose(transpose((((X|X) +transpose(X,4) ) +transpose(X,7) ) ,-5) ,-7) ) ,7) ) ,7) ) ,-7) ,7) ) ,12) ,7) ) ) ,4,6) ,-7) ,7) )
random seed used was 0 EXPR = transpose((transpose((arpeggio(((echo(echo(X,4,6) ,4,6) +transpose((X+X) ,7) ) +transpose((((X|((X+transpose(X,4) ) +transpose(X,7) ) ) +transpose(transpose(X,-5) ,12) ) +transpose(((arpeggio(X) +transpose((X+transpose(X,12) ) ,4) ) +transpose((X|X) ,7) ) ,7) ) ,12) ) ) +transpose((step((transpose(((((((transpose(transpose(X,-5) ,-7) +transpose((echo((transpose(X,-5) |X) ,4,6) +transpose(arpeggio(step(transpose(X,-5) ,12) ) ,7) ) ,4) ) +transpose(((step((X+transpose(X,12) ) ,12) |(X+X) ) +transpose(X,-7) ) ,7) ) +transpose((((transpose(X,-5) +transpose(X,7) ) +transpose(((transpose(X,-5) +transpose(transpose(X,-7) ,4) ) +transpose(transpose(X,-7) ,7) ) ,4) ) +transpose(transpose((X+transpose(X,12) ) ,-5) ,7) ) ,12) ) +transpose(((((arpeggio(shuffle(X) ) +transpose(X,12) ) +transpose(shuffle(((X+transpose(X,12) ) +X) ) ,4) ) +transpose(X,7) ) |(step(step(X,12) ,12) +transpose(echo((X|(X|X) ) ,4,6) ,12) ) ) ,7) ) +transpose(((X|X) |X) ,4) ) +transpose(transpose((transpose(((X|arpeggio(X) ) +transpose(shuffle(X) ,7) ) ,-5) +transpose((X+echo(X,4,6) ) ,7) ) ,-7) ,7) ) ,-5) |echo(((transpose(arpeggio(shuffle(transpose(transpose(X,-5) ,-5) ) ) ,-5) +transpose(shuffle(((transpose(X,-7) +shuffle(transpose(X,-5) ) ) +step(transpose(step(X,12) ,-5) ,12) ) ) ,4) ) +transpose(arpeggio((transpose(X,-5) +transpose(arpeggio(X) ,12) ) ) ,7) ) ,4,6) ) ,12) +transpose(step((shuffle((transpose(transpose(X,4) ,-7) +transpose((echo(X,4,6) +step(X,12) ) ,12) ) ) +transpose(((shuffle(X) +(shuffle(X) +transpose((X|X) ,7) ) ) +(echo(transpose(X,4) ,4,6) +transpose(X,-5) ) ) ,12) ) ,12) ,12) ) ,7) ) ,-5) |step((transpose(shuffle(step(arpeggio(arpeggio(transpose(X,-7) ) ) ,12) ) ,-5) +transpose(step(transpose(((transpose((transpose(arpeggio(X) ,-5) |shuffle(((X|X) +transpose((step(X,12) +transpose(X,7) ) ,7) ) ) ) ,-5) +transpose(arpeggio((echo(echo(X,4,6) ,4,6) +transpose((((X|X) +transpose(X,4) ) +transpose(shuffle(X) ,7) ) ,12) ) ) ,7) ) |(transpose(((transpose(echo(arpeggio(X) ,4,6) ,-7) +transpose((shuffle(transpose((X|X) ,4) ) +transpose((X+transpose((transpose(X,-7) |X) ,12) ) ,12) ) ,4) ) +transpose(step(((((X+transpose(X,7) ) +transpose(((transpose(X,-7) +transpose(transpose(X,-7) ,4) ) +transpose(X,7) ) ,4) ) +transpose(step(((X+transpose(X,4) ) +transpose(X,7) ) ,12) ,7) ) |(X+transpose(step(X,12) ,12) ) ) ,12) ,7) ) ,-5) +transpose((transpose(transpose(((arpeggio(transpose(X,-5) ) +transpose((transpose(X,-7) +(X+X) ) ,4) ) +transpose((X+transpose(transpose(X,-7) ,7) ) ,7) ) ,4) ,-7) +transpose(((((transpose(echo(X,4,6) ,-5) +transpose(arpeggio(((X+transpose(X,4) ) +transpose(X,7) ) ) ,4) ) +transpose(echo(transpose(X,4) ,4,6) ,7) ) +transpose(((transpose(X,-7) +transpose(X,4) ) +transpose(((X+transpose(X,4) ) +transpose(X,7) ) ,7) ) ,4) ) +transpose(shuffle(transpose(arpeggio(X) ,-5) ) ,7) ) ,12) ) ,7) ) ) ,-5) ,12) ,7) ) ,12) ) ,4)
random seed used was 0 EXPR = transpose(echo((arpeggio(echo(transpose((((arpeggio(((X+transpose(X,12) ) +transpose(shuffle(X) ,12) ) ) +arpeggio((X+(X+transpose(X,12) ) ) ) ) +transpose(transpose(step(X,12) ,-7) ,4) ) +transpose(step(step(((X+transpose(X,12) ) +transpose(echo(X,4,6) ,7) ) ,12) ,12) ,7) ) ,-7) ,4,6) ) +transpose((transpose(transpose(((((step((X+transpose(X,12) ) ,12) +transpose(step(X,12) ,7) ) |step(((X+transpose(X,4) ) +transpose(X,7) ) ,12) ) +transpose((step(shuffle(X) ,12) +transpose((X+transpose(transpose((X+transpose(X,12) ) ,-7) ,7) ) ,7) ) ,4) ) +transpose(transpose(shuffle(transpose(X,-5) ) ,-5) ,7) ) ,-5) ,-7) +transpose((transpose(transpose(transpose(((((X+transpose(X,12) ) +transpose(transpose(X,4) ,4) ) +transpose((X+transpose(X,12) ) ,7) ) +transpose(arpeggio(echo((X|X) ,4,6) ) ,7) ) ,-5) ,-5) ,4) +transpose(((transpose((echo(((X|X) +(X+transpose(X,12) ) ) ,4,6) +transpose(echo(echo(X,4,6) ,4,6) ,12) ) ,-5) +transpose(step((transpose(X,-5) |(((X|X) +transpose(transpose(transpose(transpose(X,-7) ,4) ,-5) ,4) ) +transpose((transpose((X|X) ,-7) +transpose(step(X,12) ,7) ) ,7) ) ) ,12) ,4) ) +transpose(((transpose(transpose(step(((X+transpose(X,4) ) +transpose(X,7) ) ,12) ,-7) ,-7) +transpose(arpeggio((shuffle((X+transpose(X,7) ) ) +arpeggio(X) ) ) ,4) ) +transpose(transpose((arpeggio(X) +transpose((X+(X+transpose(X,7) ) ) ,12) ) ,-5) ,7) ) ,7) ) ,7) ) ,7) ) ,7) ) ,4,6) ,-7)
random seed used was 0

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