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 15 generations the expression "X" became this:
(arpeggio(((shuffle(shuffle(((echo(X,4,6) |((step((X+transpose(X,7) ) ,12) +transpose(step(((X+transpose(X,4) ) +transpose(X,7) ) ,12) ,4) ) +transpose(X,7) ) ) +transpose(transpose(((step(X,12) +transpose(transpose(X,4) ,4) ) +transpose(transpose((X+transpose(X,12) ) ,-5) ,7) ) ,-5) ,7) ) ) ) +transpose(((((echo((((transpose(X,-5) +transpose(transpose(X,-7) ,4) ) +transpose(X,7) ) +transpose(transpose((X+transpose(X,12) ) ,4) ,7) ) ,4,6) +transpose(transpose((((X+transpose((X|X) ,7) ) +transpose((X+transpose(X,7) ) ,4) ) +transpose(echo(transpose(X,4) ,4,6) ,7) ) ,-7) ,4) ) +transpose((arpeggio(X) +transpose(X,7) ) ,7) ) +transpose(X,12) ) |(((X+transpose(transpose(transpose(X,-7) ,-5) ,12) ) +transpose(((((transpose((X+transpose(X,7) ) ,-5) +transpose(X,12) ) +transpose(shuffle((X+transpose(X,12) ) ) ,4) ) +transpose(arpeggio(transpose(X,-7) ) ,7) ) +((shuffle(X) |(X|X) ) +transpose((transpose((X+transpose(X,7) ) ,-5) +transpose(step((X+transpose(X,12) ) ,12) ,12) ) ,7) ) ) ,4) ) +transpose(transpose(transpose((X|echo((X+transpose(X,12) ) ,4,6) ) ,-7) ,-7) ,7) ) ) ,12) ) +((((echo((shuffle(X) +transpose(X,7) ) ,4,6) +transpose((X+X) ,12) ) +transpose(((X+transpose(X,12) ) +transpose(transpose(X,-7) ,7) ) ,-7) ) +transpose((transpose(step((X+X) ,12) ,-7) +(X+transpose((transpose(X,-5) |(X+transpose(X,7) ) ) ,7) ) ) ,7) ) +transpose((step(shuffle(transpose(transpose((X|X) ,-7) ,-7) ) ,12) +transpose((((shuffle((arpeggio(X) |transpose(X,4) ) ) +transpose(transpose((transpose(X,4) +transpose(echo((X+transpose(X,7) ) ,4,6) ,12) ) ,-5) ,12) ) +(arpeggio(echo(transpose(X,-7) ,4,6) ) +transpose(step(transpose(transpose(X,-7) ,-5) ,12) ,7) ) ) +transpose(transpose(echo(shuffle(transpose(X,-7) ) ,4,6) ,-7) ,4) ) ,12) ) ,12) ) ) ) +step(((transpose(transpose((((step((transpose(X,4) |X) ,12) |echo(((((step(X,12) +transpose(step(transpose(X,-5) ,12) ,4) ) +transpose((X|X) ,7) ) +transpose(((transpose(X,-7) |X) +transpose(echo(X,4,6) ,12) ) ,4) ) +transpose(((X+transpose(X,4) ) +transpose(X,7) ) ,7) ) ,4,6) ) +transpose(transpose(X,-7) ,-7) ) +transpose(arpeggio((arpeggio(X) |transpose((X+transpose(X,12) ) ,-7) ) ) ,12) ) ,4) ,4) +transpose(((transpose((((transpose(transpose(transpose(transpose(X,4) ,-5) ,-5) ,-5) +transpose(transpose(((X+X) +transpose(transpose(shuffle(X) ,4) ,12) ) ,-5) ,4) ) +transpose(transpose((((echo(X,4,6) +transpose((X|X) ,4) ) +transpose(X,7) ) +transpose(X,4) ) ,-7) ,7) ) +transpose(echo(shuffle((X+transpose(X,7) ) ) ,4,6) ,12) ) ,-5) +((shuffle(echo((((X+transpose(X,12) ) +transpose(((X+transpose(X,4) ) +transpose(X,7) ) ,4) ) +transpose(transpose((X+transpose(X,7) ) ,4) ,7) ) ,4,6) ) +transpose(arpeggio(((((X+transpose(X,4) ) +transpose(X,7) ) +transpose(transpose(X,-5) ,12) ) +transpose((echo((((X+transpose(X,4) ) +transpose(X,7) ) +transpose(X,12) ) ,4,6) +((X+transpose(X,7) ) +transpose(transpose(X,-7) ,12) ) ) ,12) ) ) ,4) ) +transpose(step((step(transpose(X,-5) ,12) +transpose(transpose(X,-7) ,12) ) ,12) ,7) ) ) +transpose((transpose(((echo(X,4,6) +transpose(transpose(X,4) ,-7) ) +((X+transpose((X+transpose(X,7) ) ,4) ) +transpose(X,7) ) ) ,-5) +transpose(arpeggio(transpose(step(((X+transpose(X,4) ) +transpose(X,7) ) ,12) ,-7) ) ,7) ) ,12) ) ,4) ) +transpose(shuffle(echo(step(step(echo(transpose(step(X,12) ,-7) ,4,6) ,12) ,12) ,4,6) ) ,7) ) ,12) )
random seed used was 1367631 EXPR = shuffle(((transpose(((transpose(shuffle(((((X+X) +transpose(X,12) ) +transpose(((X+transpose(X,4) ) +transpose(X,7) ) ,7) ) +transpose((X+transpose(X,12) ) ,-7) ) ) ,-5) +transpose(transpose(transpose(((arpeggio(X) +transpose(echo(X,4,6) ,4) ) +transpose(X,7) ) ,-7) ,-7) ,12) ) |shuffle(transpose(((shuffle((transpose(transpose(X,-5) ,-7) +transpose(((X+transpose(X,12) ) |X) ,12) ) ) +transpose(step((transpose((X+transpose(X,7) ) ,-7) |(X+transpose(transpose(X,4) ,12) ) ) ,12) ,7) ) +transpose(shuffle(arpeggio(transpose(X,-7) ) ) ,7) ) ,-7) ) ) ,-7) |transpose(step((shuffle(((transpose(X,-5) +transpose(step(X,12) ,12) ) +transpose(transpose((X|X) ,4) ,7) ) ) +((transpose(((transpose((X+transpose(X,7) ) ,4) +transpose((step(X,12) +transpose(step(X,12) ,12) ) ,4) ) +transpose((((X+transpose(X,4) ) +transpose(X,7) ) +((X+transpose(X,4) ) +transpose(X,7) ) ) ,7) ) ,-5) +transpose(echo(((X|X) |(transpose(shuffle(X) ,4) +(shuffle(X) +transpose((X+X) ,12) ) ) ) ,4,6) ,12) ) +transpose((((echo(X,4,6) +(X+transpose(X,7) ) ) +echo(arpeggio(X) ,4,6) ) |echo(transpose((X+transpose(shuffle(X) ,7) ) ,4) ,4,6) ) ,7) ) ) ,12) ,-5) ) +transpose((step(shuffle(transpose(transpose(transpose(X,-5) ,-7) ,-5) ) ,12) +transpose(shuffle((step(((shuffle(arpeggio(X) ) +transpose((echo((X+(X+transpose(X,12) ) ) ,4,6) +transpose(((shuffle(X) +transpose(step(X,12) ,12) ) +(((step(X,12) +transpose(shuffle(X) ,12) ) +transpose(shuffle(step(X,12) ) ,12) ) +transpose(arpeggio((X|X) ) ,12) ) ) ,12) ) ,4) ) +transpose((((X+transpose(X,12) ) +transpose(step(step(X,12) ,12) ,7) ) +transpose(arpeggio((X+transpose(echo(transpose(X,-7) ,4,6) ,12) ) ) ,12) ) ,7) ) ,12) +transpose(shuffle(((arpeggio(step(echo(X,4,6) ,12) ) |transpose((step(X,12) +transpose(X,7) ) ,4) ) +transpose(transpose(transpose((arpeggio(X) +transpose((X+transpose(X,7) ) ,12) ) ,-7) ,-5) ,7) ) ) ,12) ) ) ,12) ) ,12) ) )
random seed used was 0 EXPR = step((((step(transpose(X,-7) ,12) |echo((X+transpose((X+transpose(X,7) ) ,12) ) ,4,6) ) |(arpeggio(X) +transpose(transpose(((X+transpose(X,7) ) +transpose(transpose(X,-5) ,7) ) ,-5) ,12) ) ) +transpose(((step(step((X|X) ,12) ,12) +transpose((transpose(((X+transpose(X,4) ) +transpose(X,7) ) ,-5) +transpose(((transpose(X,4) +transpose(X,12) ) +((X+transpose(X,4) ) +transpose((X+transpose(X,12) ) ,7) ) ) ,12) ) ,12) ) +transpose(step(((X+transpose(transpose(X,4) ,4) ) +transpose((X+X) ,7) ) ,12) ,7) ) ,12) ) ,12)
random seed used was 0 EXPR = (transpose((((step((arpeggio(shuffle(step(X,12) ) ) +arpeggio(echo(shuffle(X) ,4,6) ) ) ,12) +((shuffle(((step(X,12) |shuffle(X) ) +transpose((X+(X|X) ) ,7) ) ) +transpose(step(echo(arpeggio(X) ,4,6) ,12) ,4) ) +transpose(((transpose(step(arpeggio(X) ,12) ,-7) +transpose(echo(transpose((transpose(X,-7) +transpose(shuffle(X) ,7) ) ,4) ,4,6) ,4) ) +transpose(arpeggio(arpeggio(X) ) ,7) ) ,7) ) ) +transpose(((transpose(((transpose(((X|echo(X,4,6) ) +transpose(X,7) ) ,-5) +transpose(step((transpose(X,-7) +transpose(arpeggio(X) ,7) ) ,12) ,4) ) +transpose(step(((transpose(X,-5) +transpose(shuffle(echo(X,4,6) ) ,4) ) +transpose((echo(((X+transpose(X,4) ) +transpose(X,7) ) ,4,6) +transpose(shuffle((X+X) ) ,12) ) ,7) ) ,12) ,7) ) ,-5) +transpose(transpose(((step(X,12) +transpose((step(X,12) +transpose(X,7) ) ,4) ) +transpose(shuffle(transpose(X,-5) ) ,7) ) ,4) ,4) ) +transpose(((echo(step(arpeggio(X) ,12) ,4,6) +transpose((step(echo(echo(X,4,6) ,4,6) ,12) +(arpeggio(X) +shuffle(X) ) ) ,12) ) +transpose(shuffle(echo(step((shuffle(X) +transpose(step(X,12) ,12) ) ,12) ,4,6) ) ,12) ) ,7) ) ,12) ) +((arpeggio(transpose(arpeggio(arpeggio((X+step((echo(X,4,6) +transpose(X,12) ) ,12) ) ) ) ,-7) ) +step(transpose(transpose((echo((shuffle(arpeggio((X+transpose(X,12) ) ) ) |echo(step(X,12) ,4,6) ) ,4,6) +(transpose(((transpose(((X+transpose(X,4) ) +transpose(X,7) ) ,-7) +transpose(step(transpose(X,4) ,12) ,4) ) +transpose(((step(X,12) +transpose(((X+transpose(X,4) ) +transpose(X,7) ) ,4) ) +transpose(arpeggio(X) ,7) ) ,7) ) ,-7) |X) ) ,-7) ,-7) ,12) ) +transpose(step(transpose(transpose(step((echo((transpose(X,-7) +transpose(echo(echo(X,4,6) ,4,6) ,7) ) ,4,6) +transpose(((((X+transpose(X,-5) ) |((X+transpose(X,7) ) +transpose(X,12) ) ) +transpose(transpose(transpose(X,-7) ,-7) ,12) ) |(transpose(X,-7) |(X+transpose(X,12) ) ) ) ,7) ) ,12) ,-7) ,-7) ,12) ,12) ) ) ,-7) |((arpeggio(transpose((((((((transpose(X,-7) +transpose((((X+transpose(X,7) ) +transpose((X+transpose(X,7) ) ,4) ) +transpose(transpose(X,-7) ,7) ) ,4) ) +transpose((((transpose(X,-7) +transpose((X|X) ,4) ) +transpose(((X+transpose(X,4) ) +transpose(X,7) ) ,7) ) +transpose(arpeggio(transpose(X,-7) ) ,12) ) ,7) ) +transpose(shuffle(arpeggio(arpeggio(transpose(X,-5) ) ) ) ,4) ) +transpose(arpeggio(echo(step((transpose(X,-7) +transpose(arpeggio(X) ,12) ) ,12) ,4,6) ) ,7) ) +transpose(step(arpeggio(arpeggio(transpose(X,-5) ) ) ,12) ,12) ) +transpose(transpose((step(transpose((X|(X+transpose(X,7) ) ) ,-7) ,12) |(transpose(X,-5) +transpose(transpose(X,-7) ,7) ) ) ,-7) ,12) ) +transpose((transpose((transpose(echo(step(transpose(X,-5) ,12) ,4,6) ,-7) |step(((X+transpose(X,4) ) +transpose(X,7) ) ,12) ) ,-7) +transpose(((((X+transpose(X,7) ) +transpose((X+transpose(X,7) ) ,12) ) +transpose(step(transpose(X,-7) ,12) ,7) ) +transpose((arpeggio(X) +X) ,12) ) ,7) ) ,12) ) ,-7) ) +transpose(transpose(transpose(transpose(transpose(transpose(transpose(transpose(transpose((X|X) ,-5) ,-7) ,-7) ,-7) ,-7) ,-5) ,-7) ,4) ,7) ) +transpose(transpose(((transpose(transpose(((transpose((X+transpose(transpose(X,4) ,7) ) ,-7) +transpose(echo(transpose((transpose(X,-7) +transpose(arpeggio(X) ,12) ) ,-7) ,4,6) ,4) ) +transpose((((((shuffle(X) +transpose(echo(X,4,6) ,12) ) +transpose(echo((X+X) ,4,6) ,7) ) +shuffle((X+transpose(X,7) ) ) ) +transpose(((X+transpose(((X+transpose(X,4) ) +transpose(X,7) ) ,4) ) +transpose(shuffle(X) ,7) ) ,4) ) +transpose(echo(transpose(step(shuffle(X) ,12) ,-7) ,4,6) ,7) ) ,7) ) ,4) ,-5) +transpose((transpose(arpeggio(transpose(transpose(X,-5) ,-7) ) ,-5) |transpose(((step((step(((X+transpose(X,4) ) +transpose(X,7) ) ,12) |(X+transpose(X,7) ) ) ,12) +transpose(transpose(arpeggio(X) ,4) ,4) ) +transpose(shuffle(arpeggio((transpose(shuffle(X) ,4) |echo(step((X+transpose(X,12) ) ,12) ,4,6) ) ) ) ,7) ) ,-7) ) ,12) ) +transpose((transpose(transpose((((((((echo((X+transpose(X,12) ) ,4,6) +transpose(step(step(X,12) ,12) ,4) ) +transpose((X|X) ,7) ) +((echo(X,4,6) +transpose(((X+transpose(X,7) ) +transpose(X,7) ) ,4) ) +transpose(((X|X) +transpose(X,12) ) ,7) ) ) +transpose(echo((((X+transpose(X,4) ) +transpose(X,7) ) +(X|X) ) ,4,6) ,4) ) +transpose(X,7) ) +transpose((transpose((X+transpose(X,12) ) ,-5) +transpose((((step(X,12) +(X|transpose(X,-7) ) ) +transpose(transpose(X,-5) ,4) ) +transpose((X+transpose(echo(X,4,6) ,7) ) ,7) ) ,7) ) ,7) ) +transpose(arpeggio(arpeggio((echo((X|X) ,4,6) +echo((X|X) ,4,6) ) ) ) ,12) ) ,-7) ,4) +transpose((((echo((transpose((step(transpose(X,-5) ,12) +transpose(transpose(echo(X,4,6) ,4) ,7) ) ,-7) +transpose((step(transpose(transpose(((X+transpose((X+X) ,4) ) +transpose(step(X,12) ,7) ) ,-7) ,-7) ,12) +echo(X,4,6) ) ,12) ) ,4,6) +transpose(((echo(X,4,6) +transpose(shuffle(X) ,7) ) +transpose(arpeggio(((transpose(X,-5) +transpose((X+transpose(X,12) ) ,7) ) +transpose(((X+transpose(X,4) ) +transpose(X,7) ) ,12) ) ) ,12) ) ,4) ) +transpose((((((((((X|X) +transpose(X,4) ) +transpose(X,7) ) +transpose(step((X+X) ,12) ,4) ) +transpose(shuffle(X) ,7) ) |transpose((step(X,12) +transpose(X,7) ) ,-7) ) +transpose(((echo(X,4,6) +transpose(transpose((X+transpose(X,7) ) ,-7) ,12) ) +transpose(step((X+transpose(X,12) ) ,12) ,7) ) ,4) ) +transpose(arpeggio(((transpose((transpose(X,4) +X) ,-7) +transpose((X+transpose((X+transpose(X,7) ) ,12) ) ,4) ) +transpose((((X+transpose((X+transpose(X,7) ) ,4) ) +transpose((X|X) ,7) ) +transpose(shuffle(X) ,12) ) ,7) ) ) ,7) ) +transpose(((((step(transpose(X,-5) ,12) +transpose(echo(transpose(step((X+transpose(X,7) ) ,12) ,-7) ,4,6) ,4) ) +transpose(transpose(transpose(X,4) ,-7) ,7) ) +transpose(arpeggio(((X+transpose((X+transpose(X,12) ) ,4) ) +transpose(transpose(X,-7) ,7) ) ) ,12) ) +transpose((transpose(transpose(X,-5) ,-7) +(arpeggio(X) +transpose(X,4) ) ) ,12) ) ,7) ) ,7) ) +transpose(transpose((echo(shuffle((transpose(transpose(X,-7) ,-7) +transpose(((X+transpose(X,12) ) |arpeggio(X) ) ,7) ) ) ,4,6) |shuffle(((X+transpose(X,7) ) +transpose((X+transpose(X,12) ) ,7) ) ) ) ,4) ,12) ) ,7) ) ,12) ) ,-7) ,12) ) )
random seed used was 0

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