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:
((((echo(echo((((((X|shuffle(X) ) +X) +(echo((X|X) ,4,6) +transpose(arpeggio(shuffle(X) ) ,7) ) ) +transpose(arpeggio(((X+transpose(X,4) ) +transpose((X+X) ,7) ) ) ,7) ) +(echo(step(X,12) ,4,6) +transpose(step((((X+transpose((X|echo(X,4,6) ) ,7) ) +transpose(transpose(X,-5) ,4) ) +transpose(transpose((((X+transpose(X,4) ) +transpose(X,7) ) +transpose(X,-7) ) ,-7) ,7) ) ,12) ,12) ) ) ,4,6) ,4,6) +transpose((((transpose(echo((arpeggio(shuffle((((X+transpose(X,4) ) +transpose(X,7) ) +(X+X) ) ) ) +(((X+transpose(X,12) ) |(X+X) ) |(X+((X+transpose((X|X) ,4) ) +transpose((X+transpose(X,12) ) ,7) ) ) ) ) ,4,6) ,-5) +transpose((echo(transpose((transpose(X,-7) +transpose(step(transpose(X,-7) ,12) ,12) ) ,-5) ,4,6) +transpose(arpeggio((transpose((X+X) ,-7) +(transpose(((X+transpose(X,4) ) +transpose(X,7) ) ,-7) |(transpose(X,-5) |transpose(X,-5) ) ) ) ) ,7) ) ,4) ) +transpose(shuffle(arpeggio((X+transpose(transpose(X,4) ,7) ) ) ) ,7) ) +transpose(transpose(((((transpose((transpose(step(X,12) ,4) +(X|X) ) ,4) +transpose(shuffle(((X|(X+X) ) +transpose(X,-5) ) ) ,7) ) +transpose(shuffle((X+X) ) ,4) ) +transpose(((step((((transpose(X,4) +transpose((X+transpose(X,12) ) ,4) ) +transpose(shuffle(X) ,7) ) +echo(shuffle(X) ,4,6) ) ,12) +transpose(transpose(transpose(transpose(X,-7) ,-5) ,4) ,4) ) +transpose(step(X,12) ,7) ) ,7) ) +transpose((transpose((shuffle(transpose(transpose(X,-7) ,-5) ) +((transpose(X,4) +(X+transpose(X,7) ) ) |(X+transpose(X,12) ) ) ) ,-5) +transpose((arpeggio(transpose(transpose(X,4) ,4) ) +((transpose(X,4) |(X+transpose(X,12) ) ) |transpose(X,-5) ) ) ,7) ) ,12) ) ,-7) ,12) ) ,12) ) +transpose(shuffle(((step(transpose(transpose(((shuffle(X) |(shuffle(X) |shuffle(X) ) ) +transpose((X|X) ,4) ) ,-7) ,-5) ,12) +transpose(shuffle((transpose(shuffle((X|transpose((transpose(X,4) +transpose(echo(X,4,6) ,7) ) ,4) ) ) ,4) +transpose((X+transpose(shuffle(transpose(X,-5) ) ,7) ) ,-7) ) ) ,4) ) +transpose((transpose((((X+(X+transpose(X,7) ) ) +transpose(transpose(X,4) ,4) ) +(transpose((X+echo(X,4,6) ) ,4) |(((X+X) +transpose(((X+transpose(X,4) ) +transpose(X,7) ) ,7) ) +transpose(transpose(X,-5) ,-5) ) ) ) ,4) +transpose((((arpeggio(X) |shuffle(X) ) +transpose((((((X+transpose(transpose(X,4) ,4) ) +transpose(arpeggio(shuffle(X) ) ,7) ) |step(((X+transpose(X,7) ) +step(X,12) ) ,12) ) +transpose(((echo(X,4,6) +((X|X) |transpose(X,-7) ) ) +transpose((X|X) ,-5) ) ,4) ) +transpose(transpose(arpeggio(arpeggio(X) ) ,-5) ,7) ) ,12) ) +transpose((shuffle(echo((step(X,12) |transpose(X,-7) ) ,4,6) ) |transpose((X+transpose(((X+transpose(X,12) ) +transpose(shuffle(X) ,7) ) ,4) ) ,-5) ) ,7) ) ,12) ) ,7) ) ) ,4) ) +transpose(echo(shuffle(transpose(transpose((transpose(transpose((X+transpose(X,12) ) ,-7) ,-5) |(transpose(arpeggio(X) ,4) +transpose((X|X) ,7) ) ) ,4) ,4) ) ,4,6) ,7) ) |((step(((shuffle(shuffle(((transpose(X,4) +transpose((X|X) ,-7) ) |(X+(transpose(X,-5) +transpose(step(X,12) ,7) ) ) ) ) ) +transpose((((shuffle(transpose(echo(transpose(X,-5) ,4,6) ,4) ) +arpeggio((transpose(X,4) +(X+X) ) ) ) +transpose((transpose(((transpose((X+transpose(X,12) ) ,4) +transpose((X|((X+transpose(X,4) ) +transpose(X,7) ) ) ,4) ) +transpose((X|(X+X) ) ,7) ) ,-7) |X) ,4) ) +transpose(transpose(transpose(shuffle(step(arpeggio(X) ,12) ) ,-5) ,4) ,7) ) ,4) ) +transpose(shuffle((((((step((X+X) ,12) +transpose(shuffle(X) ,-5) ) +transpose((X+echo(X,4,6) ) ,7) ) +transpose(step(shuffle(transpose(echo(X,4,6) ,-7) ) ,12) ,4) ) +transpose((step((shuffle(X) +transpose((X|X) ,12) ) ,12) +((X|X) |transpose(X,-7) ) ) ,7) ) +transpose(step(transpose(((X|X) +transpose(X,12) ) ,-5) ,12) ,7) ) ) ,7) ) ,12) +transpose(transpose((transpose(step(X,12) ,-5) |shuffle((X|X) ) ) ,-7) ,4) ) +((((transpose(transpose((transpose(transpose(X,-7) ,-5) +(transpose(X,-5) |((X+transpose(X,4) ) +transpose(X,7) ) ) ) ,-7) ,-7) |transpose(echo(transpose((transpose((X+X) ,-5) +shuffle(step(shuffle(X) ,12) ) ) ,-5) ,4,6) ,4) ) +transpose(transpose(transpose((((((echo(((shuffle(X) +transpose(transpose(X,-5) ,7) ) +transpose((((X+transpose(X,7) ) +transpose((X+transpose(X,7) ) ,4) ) +transpose((X+X) ,7) ) ,7) ) ,4,6) +transpose(transpose(transpose(transpose(X,-5) ,-5) ,-7) ,7) ) +transpose((((X+X) +transpose((((X+transpose(X,4) ) +transpose(X,7) ) +transpose(X,-7) ) ,12) ) +transpose(shuffle(transpose(X,-7) ) ,12) ) ,4) ) +transpose(((arpeggio((X+(X+transpose(X,7) ) ) ) +shuffle(echo(arpeggio(X) ,4,6) ) ) +step(shuffle(X) ,12) ) ,7) ) +transpose((((X+transpose(transpose(X,-5) ,12) ) +transpose(((transpose((transpose(transpose(step(X,12) ,4) ,-5) +(((transpose(X,-7) +transpose(((X+transpose(X,4) ) +transpose(X,7) ) ,4) ) +transpose((X+X) ,7) ) +transpose((X+transpose(X,7) ) ,12) ) ) ,-7) +transpose(arpeggio((X+transpose(transpose((X+transpose(X,7) ) ,4) ,12) ) ) ,4) ) +transpose(((shuffle(transpose(X,-7) ) +transpose((X+transpose(shuffle(X) ,7) ) ,12) ) +arpeggio(((X|X) |((X+transpose(X,4) ) +transpose(X,7) ) ) ) ) ,7) ) ,4) ) +transpose((((((shuffle(echo(X,4,6) ) +transpose((X+transpose(transpose(((X+transpose(X,4) ) +transpose(X,7) ) ,-7) ,7) ) ,4) ) +transpose((shuffle(X) +transpose(shuffle(X) ,7) ) ,7) ) +transpose(step(shuffle(shuffle(X) ) ,12) ,4) ) +transpose(((X+shuffle(X) ) +shuffle(transpose((X+transpose(X,12) ) ,-7) ) ) ,7) ) +transpose(((transpose((X+transpose(transpose(X,-5) ,7) ) ,4) |shuffle(shuffle(X) ) ) |transpose(shuffle(step(arpeggio(X) ,12) ) ,-7) ) ,12) ) ,7) ) ,4) ) +transpose(step(transpose(shuffle(shuffle((X+transpose(X,12) ) ) ) ,-5) ,12) ,7) ) ,-5) ,-5) ,4) ) +transpose(step(echo(((transpose((X+transpose(X,12) ) ,-5) +transpose((X+transpose(X,12) ) ,4) ) +transpose(((transpose(X,4) +transpose((X|X) ,4) ) +transpose(arpeggio(X) ,7) ) ,7) ) ,4,6) ,12) ,7) ) +((shuffle((transpose(echo(((shuffle((X+transpose(shuffle(X) ,12) ) ) +transpose(X,4) ) +transpose(transpose(X,-5) ,7) ) ,4,6) ,-7) |transpose(((transpose(((X+transpose(shuffle(transpose(X,-7) ) ,4) ) +transpose(X,7) ) ,-5) +transpose((X+X) ,-5) ) +transpose(((shuffle((shuffle(X) +transpose(X,7) ) ) +transpose((X+X) ,4) ) +transpose((transpose(shuffle(X) ,-7) +X) ,7) ) ,12) ) ,-7) ) ) |transpose(shuffle((transpose((transpose(echo(transpose(X,4) ,4,6) ,-5) +transpose((X+X) ,4) ) ,-5) +transpose(((transpose(X,-5) +transpose(arpeggio(X) ,12) ) +transpose((transpose(X,4) +X) ,12) ) ,12) ) ) ,-5) ) +transpose(((((transpose(arpeggio(arpeggio(X) ) ,-7) +transpose(transpose((echo(X,4,6) +transpose(transpose(X,4) ,12) ) ,-7) ,7) ) +transpose((transpose(arpeggio((X+X) ) ,-5) +echo(transpose((X+transpose(X,7) ) ,-5) ,4,6) ) ,7) ) +transpose(transpose(((shuffle(step((X|X) ,12) ) +transpose(transpose(X,-7) ,4) ) +transpose((X+transpose(shuffle(step(X,12) ) ,7) ) ,7) ) ,-7) ,4) ) +transpose((echo(step(shuffle(X) ,12) ,4,6) +transpose(transpose(shuffle(transpose((transpose(X,-5) +transpose((X+transpose(X,12) ) ,7) ) ,-7) ) ,4) ,12) ) ,7) ) ,-5) ) ) ) )
random seed used was 18 EXPR = (((transpose(((shuffle(shuffle(X) ) +transpose(X,12) ) +(X|(transpose(X,4) +transpose(X,7) ) ) ) ,4) |shuffle(transpose((transpose((transpose(X,-7) +step((X+transpose(X,7) ) ,12) ) ,-5) +(((X|transpose(X,-5) ) +transpose(transpose(X,-5) ,4) ) +transpose((transpose((X+transpose(X,12) ) ,-7) +transpose((X|X) ,4) ) ,7) ) ) ,4) ) ) |(((((step(shuffle(transpose(step(X,12) ,-5) ) ,12) |(transpose(transpose(transpose(X,4) ,4) ,4) +transpose((X|X) ,4) ) ) +transpose(((((shuffle(X) +transpose(step(transpose((X+transpose(X,7) ) ,4) ,12) ,4) ) +transpose(shuffle(transpose(X,4) ) ,7) ) +transpose((step(shuffle(X) ,12) |shuffle(transpose((X+transpose(X,12) ) ,-7) ) ) ,12) ) +transpose((((X+X) +transpose(shuffle((X|X) ) ,7) ) +(((X+transpose(X,-5) ) +transpose(((((X+transpose(X,4) ) +transpose(X,7) ) +transpose(X,4) ) +transpose(transpose(X,4) ,7) ) ,4) ) +transpose((transpose(X,4) |X) ,7) ) ) ,12) ) ,4) ) +transpose((transpose(transpose(transpose(shuffle(X) ,-5) ,4) ,-5) +((shuffle(arpeggio(transpose(shuffle(X) ,-5) ) ) +transpose((((transpose((X+transpose(X,12) ) ,-5) |(X+X) ) +transpose((transpose(X,4) +transpose(X,-7) ) ,4) ) +transpose((((echo(X,4,6) +transpose(shuffle(X) ,4) ) +transpose((X+transpose(X,7) ) ,7) ) +transpose(((X+transpose(shuffle(X) ,4) ) +transpose(X,7) ) ,12) ) ,7) ) ,4) ) +transpose(shuffle(step(((X|echo(X,4,6) ) |echo((X|X) ,4,6) ) ,12) ) ,7) ) ) ,7) ) +transpose(shuffle(((((X|X) |X) +transpose((echo(X,4,6) |(X|X) ) ,7) ) +transpose((arpeggio(transpose(X,-5) ) |((X+transpose(X,4) ) +transpose(X,7) ) ) ,7) ) ) ,7) ) +shuffle(((arpeggio((arpeggio(X) +transpose(X,-7) ) ) |transpose(((echo(X,4,6) +(X+transpose(X,12) ) ) +transpose(shuffle(shuffle(X) ) ,7) ) ,-5) ) +transpose(transpose((shuffle((X+transpose((X|X) ,7) ) ) +transpose((transpose(transpose(X,4) ,4) +transpose(X,7) ) ,12) ) ,-7) ,12) ) ) ) ) +transpose(transpose((((transpose(transpose((X+X) ,4) ,4) +((((X+X) +transpose((X|X) ,4) ) +transpose((X|X) ,7) ) |X) ) |transpose(((((X+transpose(X,4) ) +transpose(X,7) ) +transpose(X,4) ) +transpose(transpose(X,4) ,7) ) ,4) ) +transpose(shuffle(transpose(shuffle(shuffle(step(shuffle(X) ,12) ) ) ,-7) ) ,12) ) ,-5) ,7) )
random seed used was 0 EXPR = (shuffle((transpose(shuffle((((shuffle(X) +transpose(arpeggio(echo(shuffle(transpose(X,-7) ) ,4,6) ) ,4) ) +transpose(shuffle(transpose(step(X,12) ,-7) ) ,7) ) +transpose((((((X+transpose(X,4) ) +transpose(X,7) ) +transpose(X,4) ) +transpose(transpose(X,-5) ,7) ) +(transpose(echo(X,4,6) ,4) +transpose((X+shuffle(X) ) ,12) ) ) ,12) ) ) ,-7) |(shuffle(transpose(transpose((X+X) ,-7) ,4) ) |transpose(arpeggio(((X+transpose(X,12) ) |shuffle(echo(X,4,6) ) ) ) ,-7) ) ) ) +transpose((transpose(transpose((transpose(transpose(X,4) ,4) |transpose(shuffle(arpeggio((X|X) ) ) ,-7) ) ,-7) ,4) |step((step((transpose(echo(transpose(X,4) ,4,6) ,4) +transpose(((step((X+X) ,12) +transpose(transpose((X+transpose(X,7) ) ,-5) ,12) ) +transpose(((echo(X,4,6) +transpose(transpose(X,-5) ,4) ) +transpose(X,7) ) ,12) ) ,7) ) ,12) +(((step(transpose(((X+transpose(X,4) ) +transpose(X,7) ) ,-5) ,12) +transpose((shuffle((((shuffle(X) +transpose(X,4) ) +transpose(shuffle(X) ,7) ) |step(X,12) ) ) +transpose((shuffle(shuffle(X) ) |(shuffle(X) +transpose((transpose(X,-5) +transpose((X|X) ,7) ) ,12) ) ) ,7) ) ,4) ) +transpose((transpose((X|X) ,4) +transpose((((shuffle(X) |X) +transpose(shuffle((X+X) ) ,4) ) +transpose(arpeggio(X) ,7) ) ,12) ) ,7) ) |transpose(transpose((transpose(X,-7) +(shuffle(X) |(X|X) ) ) ,-5) ,-5) ) ) ,12) ) ,7) )
random seed used was 0 EXPR = (((((arpeggio((step(transpose(shuffle(transpose(transpose(transpose(X,4) ,4) ,-7) ) ,-5) ,12) |((arpeggio(X) |X) +(transpose(X,4) +transpose(X,12) ) ) ) ) |(((((((X+transpose(X,4) ) +transpose(X,7) ) |(X+transpose(X,12) ) ) +step(transpose(transpose((X+(X|X) ) ,-5) ,4) ,12) ) +((arpeggio((shuffle(X) +transpose(shuffle(X) ,7) ) ) +transpose(transpose((X+X) ,-7) ,12) ) |((shuffle(arpeggio(transpose(X,-5) ) ) +transpose(((X|X) +transpose(shuffle(X) ,12) ) ,4) ) +transpose((X+transpose(X,7) ) ,7) ) ) ) |transpose(((((X+X) +transpose(step(X,12) ,4) ) +transpose(X,7) ) +(X+transpose(X,7) ) ) ,4) ) |(((echo((shuffle((X+(X+transpose(X,12) ) ) ) |transpose(shuffle(transpose(((X+transpose(X,4) ) +transpose(X,7) ) ,4) ) ,-7) ) ,4,6) +transpose(((transpose(((X|X) +transpose(X,7) ) ,-5) +transpose(transpose((X+X) ,-5) ,-5) ) +transpose(transpose(shuffle((X|(X+X) ) ) ,-7) ,7) ) ,7) ) +transpose(transpose((shuffle(X) +transpose(transpose(X,-7) ,7) ) ,4) ,4) ) +transpose((transpose(transpose(shuffle((X+X) ) ,-7) ,-5) +transpose(transpose(X,4) ,12) ) ,7) ) ) ) +transpose((shuffle(echo(transpose(((X+transpose(X,4) ) +transpose(X,7) ) ,4) ,4,6) ) +(transpose(transpose(transpose((X+X) ,4) ,4) ,-7) +transpose((transpose(transpose(shuffle(shuffle(X) ) ,-7) ,-7) +echo(transpose(X,-7) ,4,6) ) ,12) ) ) ,4) ) +transpose(((transpose(shuffle(((X|X) |step(transpose(X,4) ,12) ) ) ,-5) +transpose(transpose((((X+transpose(X,4) ) +transpose(X,7) ) +X) ,4) ,7) ) |arpeggio(transpose((transpose(arpeggio(transpose(X,-5) ) ,-5) +transpose((arpeggio(X) +X) ,12) ) ,-5) ) ) ,7) ) +transpose(transpose(echo(transpose(transpose((arpeggio(X) +arpeggio(X) ) ,-5) ,-5) ,4,6) ,-5) ,7) ) |((transpose(echo(transpose(((shuffle(((X|X) +shuffle(((transpose(X,-7) +transpose(transpose(X,4) ,4) ) +transpose(transpose(X,4) ,7) ) ) ) ) |shuffle(transpose(shuffle(transpose(X,4) ) ,4) ) ) +echo(((transpose(transpose(X,-5) ,4) +transpose(X,4) ) +transpose(X,7) ) ,4,6) ) ,-7) ,4,6) ,-7) +transpose(transpose(transpose((shuffle(arpeggio(((((transpose(transpose(X,4) ,-5) +transpose(step(shuffle(X) ,12) ,4) ) +transpose((transpose(shuffle((X+transpose(X,7) ) ) ,-5) |step(X,12) ) ,7) ) |step(shuffle(X) ,12) ) +((transpose(shuffle(transpose(X,4) ) ,4) +echo((X|X) ,4,6) ) |transpose(transpose(shuffle(X) ,4) ,4) ) ) ) ) +transpose((((((transpose(((X+transpose(X,7) ) +transpose(transpose(X,-7) ,7) ) ,4) +transpose(transpose(transpose(X,4) ,-7) ,4) ) +transpose(arpeggio(((X|X) +transpose((X+step(X,12) ) ,12) ) ) ,7) ) |shuffle(((((X+transpose(X,4) ) +transpose(X,7) ) |transpose(X,-7) ) +(echo(X,4,6) |transpose(X,4) ) ) ) ) |arpeggio(transpose(X,-5) ) ) +transpose(((((transpose(shuffle((((transpose(X,4) +transpose((X+transpose(X,7) ) ,7) ) +transpose(transpose(step(X,12) ,-5) ,4) ) +transpose((X+X) ,7) ) ) ,4) +shuffle(transpose(shuffle(X) ,-5) ) ) +transpose(echo((shuffle(X) |(X|((X+transpose(X,4) ) +transpose(X,7) ) ) ) ,4,6) ,4) ) +transpose((shuffle(shuffle((((X+transpose(X,12) ) |X) +step((X+transpose(X,7) ) ,12) ) ) ) +echo((echo(X,4,6) +X) ,4,6) ) ,7) ) +transpose(transpose(shuffle((transpose(X,4) |transpose(X,-7) ) ) ,4) ,12) ) ,12) ) ,7) ) ,-5) ,4) ,4) ) +transpose((((arpeggio(step((((X+transpose(X,4) ) +transpose(X,7) ) |(echo(X,4,6) +transpose((X+transpose(X,7) ) ,7) ) ) ,12) ) +shuffle(echo((transpose(X,4) +transpose(X,12) ) ,4,6) ) ) +transpose((((transpose(transpose(shuffle(X) ,-7) ,4) +transpose(transpose(X,-7) ,4) ) +transpose(((X|transpose(X,-5) ) +transpose(X,-7) ) ,4) ) +transpose((((shuffle(X) +transpose(arpeggio((X+X) ) ,4) ) +transpose((X+transpose(X,12) ) ,7) ) +(transpose(X,-7) +transpose((X+transpose(X,7) ) ,4) ) ) ,7) ) ,12) ) +transpose(arpeggio(shuffle(transpose((arpeggio(((X|X) +transpose((shuffle(X) +transpose(X,12) ) ,12) ) ) |echo((X|shuffle(X) ) ,4,6) ) ,4) ) ) ,4) ) ,7) ) )
random seed used was 0

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