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:
Seed:
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Phrase for X:
# of Tracks:
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After 20 generations the expression "X" became this:
transpose(arpeggio(transpose(transpose((transpose((((shuffle(shuffle((step(step(X,12) ,12) |(shuffle(X) +transpose((X|X) ,7) ) ) ) ) +transpose(((step(transpose(((echo((step(X,12) +transpose(X,12) ) ,4,6) +transpose(arpeggio(shuffle(arpeggio(X) ) ) ,4) ) +transpose((echo(X,4,6) |arpeggio(arpeggio(shuffle(X) ) ) ) ,7) ) ,4) ,12) +transpose(step(transpose(shuffle(shuffle(X) ) ,4) ,12) ,4) ) +transpose((echo(transpose(transpose(transpose(X,-5) ,-7) ,-5) ,4,6) |transpose((X+transpose(X,4) ) ,4) ) ,7) ) ,4) ) +transpose(shuffle((transpose((step(X,12) +transpose(transpose(echo(X,4,6) ,-5) ,7) ) ,-5) |shuffle(transpose(step(shuffle(X) ,12) ,4) ) ) ) ,7) ) +shuffle(transpose(step(((X+(X+X) ) |shuffle(X) ) ,12) ,-7) ) ) ,4) +transpose((echo(shuffle(echo((step(X,12) +shuffle(X) ) ,4,6) ) ,4,6) +((transpose(((transpose(((X+X) |(X|X) ) ,-7) +transpose(shuffle((transpose(X,-7) +((X+transpose(X,4) ) +transpose(arpeggio(X) ,7) ) ) ) ,7) ) +transpose((echo(transpose(((arpeggio(X) +transpose((X+transpose(X,12) ) ,4) ) +transpose(arpeggio(X) ,7) ) ,-7) ,4,6) +transpose((step((X+X) ,12) +echo(X,4,6) ) ,4) ) ,7) ) ,-7) |shuffle(echo(arpeggio(arpeggio(X) ) ,4,6) ) ) |arpeggio(transpose(transpose(shuffle(transpose(transpose(arpeggio(X) ,-5) ,-5) ) ,4) ,4) ) ) ) ,12) ) ,4) ,4) ) ,-5)
random seed used was 143011390 EXPR = (transpose(echo(step(((transpose(((transpose(shuffle(arpeggio(X) ) ,4) +transpose(echo(X,4,6) ,4) ) +transpose((echo(transpose(X,4) ,4,6) +transpose(transpose(arpeggio((arpeggio(X) |X) ) ,4) ,12) ) ,7) ) ,-7) +transpose(transpose(step(step(echo(shuffle(step(transpose(echo(X,4,6) ,-7) ,12) ) ,4,6) ,12) ,12) ,-5) ,12) ) |echo(arpeggio(transpose(shuffle((X+transpose(transpose(transpose(X,-7) ,-7) ,12) ) ) ,-5) ) ,4,6) ) ,12) ,4,6) ,-5) +transpose(shuffle(((transpose((arpeggio(step(arpeggio(((transpose(echo(echo(((shuffle(transpose(X,-7) ) +transpose(transpose(echo(X,4,6) ,-5) ,4) ) +transpose(((X+transpose(X,7) ) +transpose((X+X) ,12) ) ,7) ) ,4,6) ,4,6) ,-5) +transpose((transpose((arpeggio(arpeggio((X|X) ) ) +transpose(((X+transpose(arpeggio(X) ,4) ) +transpose(X,7) ) ,-5) ) ,-7) |(step(shuffle(transpose(X,-7) ) ,12) +transpose(((X+X) +echo((transpose(X,4) +transpose(X,12) ) ,4,6) ) ,12) ) ) ,4) ) +transpose((echo(((echo(X,4,6) +transpose(arpeggio(transpose(transpose(X,-7) ,-5) ) ,4) ) +arpeggio(echo(((transpose(X,-5) +transpose((X|X) ,4) ) +transpose(step(X,12) ,7) ) ,4,6) ) ) ,4,6) +transpose((step(X,12) +((shuffle(((transpose(X,-5) +transpose(transpose(X,4) ,4) ) +transpose(transpose(X,4) ,7) ) ) +transpose(shuffle(step(X,12) ) ,4) ) +transpose((transpose(arpeggio(X) ,4) +((X+transpose(X,12) ) +transpose(X,7) ) ) ,7) ) ) ,7) ) ,7) ) ) ,12) ) |transpose(transpose(shuffle(((shuffle(transpose(transpose((transpose(X,-5) +transpose(X,-7) ) ,4) ,4) ) +transpose(transpose((arpeggio((arpeggio(shuffle(X) ) +transpose(echo(arpeggio(shuffle(X) ) ,4,6) ,7) ) ) +transpose((echo(echo(X,4,6) ,4,6) +transpose((echo(X,4,6) +transpose(((X+transpose(X,4) ) +transpose(X,7) ) ,7) ) ,12) ) ,12) ) ,4) ,4) ) +transpose(transpose((transpose(arpeggio(X) ,-7) +arpeggio(X) ) ,-7) ,7) ) ) ,-5) ,-5) ) ,-7) +transpose((transpose(((shuffle(step(((transpose(transpose(transpose(arpeggio(X) ,4) ,4) ,-7) +transpose(echo(transpose(((X+transpose(arpeggio(X) ,4) ) +transpose(X,7) ) ,-7) ,4,6) ,4) ) +transpose((echo(step(transpose(transpose(X,-5) ,-7) ,12) ,4,6) +transpose(step(shuffle(X) ,12) ,7) ) ,7) ) ,12) ) +transpose(transpose(transpose(transpose(echo((step(X,12) +arpeggio(X) ) ,4,6) ,-7) ,4) ,-5) ,7) ) +transpose((shuffle(shuffle(transpose(transpose(arpeggio(transpose(echo((X+X) ,4,6) ,-5) ) ,-7) ,-5) ) ) +transpose(echo(transpose(echo(step((transpose(X,-5) |(X+X) ) ,12) ,4,6) ,4) ,4,6) ,4) ) ,12) ) ,-7) +transpose(echo((((transpose((((step(step(X,12) ,12) +transpose(echo(transpose(X,-5) ,4,6) ,4) ) +transpose(transpose(arpeggio(X) ,-7) ,7) ) +(X|transpose(X,-5) ) ) ,-7) +((step(transpose((X+transpose(X,7) ) ,-7) ,12) +transpose(echo(arpeggio(X) ,4,6) ,4) ) +transpose(arpeggio(arpeggio((arpeggio(arpeggio(X) ) +transpose(shuffle(echo(X,4,6) ) ,7) ) ) ) ,7) ) ) +transpose(((transpose(transpose((X+transpose(X,7) ) ,-7) ,-5) +arpeggio(arpeggio(step(transpose((X+X) ,-7) ,12) ) ) ) |transpose((shuffle(arpeggio(arpeggio(X) ) ) +transpose(shuffle(arpeggio(X) ) ,12) ) ,4) ) ,4) ) +transpose((shuffle(echo(shuffle(X) ,4,6) ) |arpeggio(step(shuffle(echo(shuffle(((shuffle(X) |step(X,12) ) +transpose(transpose(arpeggio(X) ,-5) ,12) ) ) ,4,6) ) ,12) ) ) ,7) ) ,4,6) ,12) ) ,4) ) +transpose(transpose((transpose(arpeggio(echo(transpose(X,4) ,4,6) ) ,-5) +echo((arpeggio(((X+transpose(transpose(X,4) ,12) ) |step(X,12) ) ) +shuffle((transpose(transpose(X,4) ,-5) |(X+transpose(X,12) ) ) ) ) ,4,6) ) ,4) ,7) ) ) ,12) )
random seed used was 0 EXPR = transpose(transpose(transpose(arpeggio((shuffle((echo((arpeggio((transpose(((shuffle(echo(X,4,6) ) +transpose(shuffle(X) ,4) ) +transpose(transpose((X+X) ,4) ,7) ) ,-7) |(((X+transpose(X,12) ) +X) +transpose(((X+transpose(X,4) ) +transpose(X,7) ) ,12) ) ) ) +transpose(shuffle(transpose(shuffle(((transpose(X,-7) +X) +transpose((step(X,12) +transpose(X,12) ) ,7) ) ) ,-7) ) ,7) ) ,4,6) |((X+transpose(transpose(X,-7) ,12) ) +transpose(echo(echo(X,4,6) ,4,6) ,12) ) ) ) +shuffle((((step((((echo((X+transpose(X,7) ) ,4,6) |transpose((X+transpose(echo(X,4,6) ,12) ) ,-7) ) +transpose((transpose((arpeggio(transpose(X,4) ) |shuffle((transpose(X,-7) +transpose(transpose(X,4) ,7) ) ) ) ,-5) +transpose((step(transpose(step(X,12) ,-7) ,12) +shuffle(step(transpose(X,4) ,12) ) ) ,7) ) ,7) ) |(shuffle(step((((arpeggio(X) +transpose((X+X) ,4) ) +transpose(transpose(X,-7) ,7) ) +transpose(arpeggio(X) ,7) ) ,12) ) +transpose(shuffle((arpeggio(((X+transpose(X,4) ) +transpose(X,7) ) ) +transpose(X,12) ) ) ,12) ) ) ,12) |transpose(shuffle(transpose(arpeggio((step(X,12) |(X|X) ) ) ,-5) ) ,-7) ) +transpose(shuffle((transpose(arpeggio(step(arpeggio(X) ,12) ) ,-7) +shuffle(((arpeggio(shuffle(X) ) +transpose(transpose(arpeggio(X) ,-7) ,12) ) +(transpose((((X+transpose(X,4) ) +transpose(X,7) ) |X) ,-7) +X) ) ) ) ) ,4) ) +transpose(shuffle((echo(transpose((transpose(X,-5) +transpose((X+transpose(X,12) ) ,7) ) ,-5) ,4,6) +transpose(step(transpose(shuffle(shuffle(X) ) ,4) ,12) ,4) ) ) ,7) ) ) ) ) ,4) ,-5) ,-7)
random seed used was 0 EXPR = (step((arpeggio(arpeggio(((transpose((((X|X) +transpose(transpose(shuffle(X) ,-5) ,7) ) +transpose(echo((((X+transpose(X,4) ) +transpose(X,7) ) +X) ,4,6) ,7) ) ,-5) +step(transpose(transpose((step(X,12) +transpose(X,12) ) ,-5) ,-5) ,12) ) |transpose((echo(arpeggio(transpose(shuffle(X) ,-7) ) ,4,6) |arpeggio(arpeggio(transpose(arpeggio((shuffle(X) +(X+transpose(X,12) ) ) ) ,-7) ) ) ) ,-5) ) ) ) +(echo(transpose(step(arpeggio(echo(step(step(step(transpose(arpeggio(X) ,-5) ,12) ,12) ,12) ,4,6) ) ,12) ,4) ,4,6) +((arpeggio(step((((shuffle(shuffle((transpose(X,-5) +step(transpose(X,4) ,12) ) ) ) +transpose(echo(transpose(shuffle((step(X,12) +transpose(X,7) ) ) ,-5) ,4,6) ,4) ) +transpose(arpeggio(transpose((((X+transpose((X+transpose(X,12) ) ,12) ) +transpose(shuffle(X) ,4) ) +transpose((shuffle(X) +transpose(arpeggio(X) ,12) ) ,7) ) ,4) ) ,7) ) +((arpeggio(transpose(echo((((X+transpose(X,7) ) +transpose(echo(X,4,6) ,7) ) |(X+transpose(X,12) ) ) ,4,6) ,-7) ) +transpose(transpose(((step(step(shuffle(X) ,12) ,12) +transpose((arpeggio((step(X,12) +transpose(transpose(shuffle(X) ,-5) ,7) ) ) +step((step(X,12) +echo(X,4,6) ) ,12) ) ,4) ) +transpose((echo(((echo(X,4,6) +transpose(X,7) ) |arpeggio(X) ) ,4,6) +arpeggio((transpose(X,-7) +(transpose(X,4) +transpose(X,4) ) ) ) ) ,7) ) ,-7) ,4) ) +transpose(((echo(((((X+transpose(X,12) ) +transpose(X,12) ) |transpose((X+X) ,4) ) +transpose((echo(X,4,6) |X) ,12) ) ,4,6) +transpose(shuffle(transpose(shuffle(step(X,12) ) ,4) ) ,7) ) |(shuffle(shuffle(step((arpeggio(X) +transpose(X,12) ) ,12) ) ) +(transpose(transpose(echo(X,4,6) ,4) ,-5) |((transpose(X,-7) +transpose(transpose(X,-7) ,12) ) +transpose(arpeggio(step(X,12) ) ,12) ) ) ) ) ,7) ) ) ,12) ) +transpose((transpose((transpose(echo((step(arpeggio(arpeggio(arpeggio((X+transpose(X,7) ) ) ) ) ,12) |((arpeggio(X) +transpose(transpose(transpose(arpeggio(X) ,4) ,4) ,7) ) |((((echo(X,4,6) +step(X,12) ) +transpose(X,4) ) +transpose((X+transpose(X,12) ) ,7) ) +transpose((((X|X) +transpose(transpose(X,-7) ,4) ) +transpose(X,7) ) ,7) ) ) ) ,4,6) ,-7) +echo((shuffle(echo(arpeggio(transpose(shuffle(X) ,4) ) ,4,6) ) |((transpose((transpose(transpose(X,-5) ,-7) +transpose(transpose(step(X,12) ,4) ,7) ) ,-7) |shuffle(transpose(X,4) ) ) +(transpose(X,-7) |step((X|X) ,12) ) ) ) ,4,6) ) ,-5) +transpose(echo(step((shuffle(shuffle(transpose(step(arpeggio(X) ,12) ,4) ) ) +((transpose((((X+transpose(X,4) ) +transpose(X,7) ) +(transpose(X,4) +transpose(echo(X,4,6) ,7) ) ) ,4) |transpose(X,4) ) +transpose((transpose(transpose((step(X,12) +transpose(transpose(X,-7) ,7) ) ,4) ,4) +step(echo((X+transpose(X,7) ) ,4,6) ,12) ) ,12) ) ) ,12) ,4,6) ,12) ) ,4) ) +transpose((arpeggio(arpeggio((((arpeggio((((X+transpose(transpose(X,4) ,4) ) +transpose(arpeggio(X) ,7) ) |arpeggio(X) ) ) |transpose((echo(X,4,6) +arpeggio(X) ) ,-5) ) |shuffle(((step(step(X,12) ,12) +transpose(X,4) ) +transpose(echo(((arpeggio(X) +(step(X,12) +transpose((X+transpose(X,12) ) ,12) ) ) +echo((arpeggio(X) +transpose(step(X,12) ,12) ) ,4,6) ) ,4,6) ,7) ) ) ) |transpose(step(shuffle(transpose(echo(X,4,6) ,4) ) ,12) ,-5) ) ) ) +(shuffle(arpeggio(transpose(shuffle(arpeggio(X) ) ,4) ) ) +arpeggio(step(transpose(echo(shuffle(arpeggio(X) ) ,4,6) ,-5) ,12) ) ) ) ,7) ) ) ) ,12) +echo(step(arpeggio(transpose(transpose(step(transpose(transpose(step((step((shuffle(step(X,12) ) +step(X,12) ) ,12) +((step(X,12) +echo(arpeggio(X) ,4,6) ) +transpose(shuffle(arpeggio(step(transpose(X,4) ,12) ) ) ,12) ) ) ,12) ,-7) ,-5) ,12) ,-7) ,-7) ) ,12) ,4,6) )
random seed used was 0

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