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 16 generations the expression "X" became this:
((transpose(((transpose(echo(((((X+transpose(X,7) ) |((X|X) +transpose(arpeggio(X) ,12) ) ) +transpose(transpose(((X|X) |transpose(X,4) ) ,4) ,4) ) +transpose(shuffle(X) ,7) ) ,4,6) ,-7) +transpose(arpeggio(transpose(X,-7) ) ,12) ) |transpose(((transpose(arpeggio(X) ,-7) |arpeggio(shuffle(X) ) ) +transpose((X+transpose(X,7) ) ,12) ) ,4) ) ,-5) +(transpose((transpose(transpose(((X+transpose(X,4) ) +transpose(X,7) ) ,4) ,-7) +transpose(transpose(shuffle(transpose(X,4) ) ,-7) ,12) ) ,-5) |arpeggio((transpose(transpose(transpose(transpose((transpose((X|(X+transpose(X,7) ) ) ,4) +transpose(X,4) ) ,4) ,-7) ,-7) ,-5) +transpose((transpose((step(((X+transpose(X,7) ) +transpose(transpose(X,-7) ,7) ) ,12) +transpose(step((arpeggio((X+transpose(X,12) ) ) +transpose(echo(echo(shuffle(X) ,4,6) ,4,6) ,12) ) ,12) ,12) ) ,-7) |transpose(((((((transpose((X|X) ,-7) +transpose(transpose(transpose(X,-5) ,4) ,4) ) +transpose(transpose(X,-7) ,7) ) |(echo(X,4,6) |shuffle(X) ) ) +transpose(((X|X) +transpose((transpose(shuffle(X) ,-7) |transpose(transpose(X,-7) ,-5) ) ,12) ) ,4) ) +transpose((echo(X,4,6) |((transpose(X,4) |echo(X,4,6) ) +transpose(arpeggio(X) ,12) ) ) ,7) ) +transpose(step(echo((transpose(arpeggio(X) ,-7) |((transpose(X,-5) +transpose(X,4) ) +transpose(transpose(X,4) ,7) ) ) ,4,6) ,12) ,7) ) ,-5) ) ,7) ) ) ) ) +(step((transpose(transpose((shuffle((echo(X,4,6) +transpose((transpose(X,-7) +X) ,12) ) ) |(shuffle(((X+transpose(X,12) ) +transpose(X,12) ) ) +transpose(((X|X) +transpose(X,7) ) ,12) ) ) ,4) ,4) +transpose((transpose(((transpose(step(((X+transpose(echo(X,4,6) ,4) ) +transpose(arpeggio(X) ,7) ) ,12) ,-7) |(arpeggio(step(X,12) ) +transpose(((((X+transpose(X,4) ) +transpose(X,7) ) |(X+transpose(X,7) ) ) +transpose((X+transpose(arpeggio(X) ,7) ) ,7) ) ,12) ) ) +transpose(transpose((step(((transpose(X,-7) +transpose(((X+transpose(X,4) ) +transpose(X,7) ) ,4) ) +transpose(shuffle(X) ,7) ) ,12) +transpose((echo(transpose(X,-5) ,4,6) |echo(transpose(X,-7) ,4,6) ) ,7) ) ,-5) ,12) ) ,-7) |((((((transpose((X|X) ,-5) +transpose(arpeggio(transpose(X,4) ) ,7) ) +transpose(arpeggio(transpose(X,-7) ) ,12) ) +transpose(echo((((X+transpose(X,4) ) +transpose(X,7) ) |arpeggio(arpeggio(X) ) ) ,4,6) ,4) ) +transpose((step(((X+transpose(X,4) ) +transpose(X,7) ) ,12) +transpose(transpose((transpose(X,4) +(X+transpose(X,7) ) ) ,-7) ,7) ) ,7) ) +transpose((((transpose((X+transpose((X+transpose(X,12) ) ,12) ) ,-5) +transpose(((X+transpose(X,12) ) +transpose(arpeggio(transpose(X,-5) ) ,12) ) ,4) ) +transpose(transpose(shuffle(transpose(X,4) ) ,4) ,7) ) +step(arpeggio((X|X) ) ,12) ) ,-5) ) +transpose(((step((((transpose((X+transpose(X,12) ) ,-5) +transpose((((X|step(X,12) ) +transpose(((X+transpose(transpose(X,4) ,4) ) +transpose(X,7) ) ,4) ) +transpose(X,7) ) ,4) ) +transpose(arpeggio(((transpose(X,-7) +transpose(X,4) ) +transpose(X,7) ) ) ,7) ) |transpose((transpose(X,-5) +transpose(step(X,12) ,12) ) ,-5) ) ,12) +transpose(shuffle((X+transpose(X,12) ) ) ,4) ) +transpose((X|(((X+transpose((X+X) ,12) ) +(arpeggio(X) |((X+transpose(X,4) ) +transpose(X,7) ) ) ) +transpose(transpose(echo(step(X,12) ,4,6) ,4) ,7) ) ) ,7) ) ,12) ) ) ,12) ) ,12) |(((step((arpeggio(shuffle(((transpose(X,-5) +arpeggio(X) ) |step((transpose(X,-5) +transpose((transpose(X,-7) |transpose(X,-7) ) ,12) ) ,12) ) ) ) +transpose(transpose(transpose(((arpeggio(transpose(X,-7) ) +transpose(echo((transpose((((X+transpose(X,4) ) +transpose(X,7) ) +transpose((X+transpose(X,7) ) ,12) ) ,-7) |transpose(transpose((X|X) ,-5) ,4) ) ,4,6) ,4) ) +transpose(((arpeggio(transpose(transpose(X,-7) ,-7) ) +transpose(((X+transpose(X,12) ) |transpose(X,-5) ) ,12) ) +(echo(transpose(((X+transpose(X,4) ) +transpose(X,7) ) ,4) ,4,6) +transpose(X,12) ) ) ,7) ) ,-5) ,4) ,7) ) ,12) +transpose((arpeggio((transpose(((echo(transpose(X,4) ,4,6) +transpose(transpose(X,4) ,4) ) +transpose(transpose(X,4) ,7) ) ,4) +transpose(((transpose(echo(transpose(X,4) ,4,6) ,-5) +transpose(shuffle(echo(X,4,6) ) ,12) ) +transpose(arpeggio(X) ,-7) ) ,12) ) ) |echo(transpose((transpose(shuffle(X) ,4) |transpose(transpose(transpose(X,-5) ,-5) ,-5) ) ,-7) ,4,6) ) ,7) ) +transpose((echo((transpose(transpose(step(transpose((X+transpose(X,7) ) ,-5) ,12) ,4) ,-7) +transpose(echo((X|X) ,4,6) ,4) ) ,4,6) |((shuffle(((X|X) +transpose(arpeggio(arpeggio(X) ) ,12) ) ) |transpose(arpeggio(((X+transpose(echo(X,4,6) ,12) ) +transpose(transpose((X+transpose(X,12) ) ,4) ,12) ) ) ,-7) ) +transpose(((step(step(transpose(((transpose(transpose((X+X) ,4) ,-5) +transpose(((X+transpose(X,7) ) |transpose(X,-5) ) ,4) ) +transpose((((X+transpose(shuffle(X) ,4) ) +transpose((X+transpose(X,7) ) ,7) ) +transpose((transpose(X,-7) |(X+X) ) ,7) ) ,7) ) ,4) ,12) ,12) |step((((X|X) +transpose(transpose((X+transpose(X,12) ) ,-5) ,4) ) +transpose(arpeggio(((X+transpose(transpose(X,-5) ,4) ) +transpose((X+transpose(X,7) ) ,7) ) ) ,7) ) ,12) ) |step(((X+transpose(X,7) ) +transpose(transpose((transpose(shuffle(X) ,4) +transpose(echo((X+transpose(X,12) ) ,4,6) ,12) ) ,-7) ,12) ) ,12) ) ,7) ) ) ,7) ) +transpose(step((arpeggio(transpose((transpose(shuffle(transpose(arpeggio(X) ,4) ) ,-5) |step(arpeggio((X|echo(transpose(X,-7) ,4,6) ) ) ,12) ) ,4) ) +((transpose(transpose(((echo((X+transpose(X,7) ) ,4,6) +transpose(echo(echo(step(X,12) ,4,6) ,4,6) ,4) ) +transpose(transpose(transpose(X,-5) ,-5) ,7) ) ,4) ,-7) +transpose((shuffle(transpose(transpose(transpose(X,4) ,4) ,4) ) |(transpose(shuffle(X) ,-7) |((((((transpose(X,4) +transpose(step(transpose(X,-7) ,12) ,7) ) +transpose(((X|X) |transpose(X,-5) ) ,4) ) +transpose(transpose(X,4) ,7) ) +transpose(arpeggio(echo((transpose(X,-5) |X) ,4,6) ) ,4) ) +transpose((transpose(X,4) +transpose(transpose(X,4) ,7) ) ,7) ) +transpose(transpose(transpose((X|((X+transpose((X+transpose(X,7) ) ,4) ) +transpose(X,7) ) ) ,4) ,-5) ,7) ) ) ) ,12) ) |echo((((transpose(X,-7) +transpose(X,4) ) +transpose(step(X,12) ,7) ) |echo(transpose(step(X,12) ,4) ,4,6) ) ,4,6) ) ) ,12) ,7) ) ) )
random seed used was 10 EXPR = (echo((echo(((transpose(transpose(((transpose(echo(shuffle(echo(X,4,6) ) ,4,6) ,-7) +transpose((shuffle((transpose(transpose(X,-5) ,-5) +((X+transpose(((X+transpose(X,4) ) +transpose(X,7) ) ,12) ) +transpose(transpose(echo(X,4,6) ,4) ,12) ) ) ) +transpose(shuffle(X) ,7) ) ,4) ) +transpose(transpose(step((transpose(X,4) +transpose(X,4) ) ,12) ,-7) ,7) ) ,-5) ,4) +transpose(transpose((((transpose(transpose(X,4) ,4) |transpose((transpose((X|X) ,-5) +transpose(transpose((X+transpose(X,7) ) ,-5) ,7) ) ,-7) ) +transpose((transpose(echo(transpose(step(((X+transpose(X,4) ) +transpose(X,7) ) ,12) ,-7) ,4,6) ,4) |transpose((shuffle(transpose(X,-5) ) +transpose(X,4) ) ,-7) ) ,4) ) +transpose(transpose(arpeggio(step(transpose(arpeggio(X) ,-5) ,12) ) ,4) ,7) ) ,-5) ,12) ) +((((echo(transpose(X,-7) ,4,6) +transpose(((transpose(X,-7) +transpose(transpose(echo(transpose(X,-7) ,4,6) ,4) ,12) ) +transpose(transpose((X+transpose(arpeggio(X) ,12) ) ,-7) ,12) ) ,7) ) +transpose(shuffle(transpose(((transpose(((transpose(X,4) +transpose(transpose(X,-7) ,7) ) +transpose(transpose((X+X) ,4) ,12) ) ,-7) +transpose(echo((shuffle((X|X) ) +transpose(((X+transpose(X,7) ) |X) ,12) ) ,4,6) ,4) ) +transpose((step(echo(X,4,6) ,12) +transpose((transpose(X,4) +transpose(shuffle(X) ,7) ) ,12) ) ,7) ) ,-5) ) ,4) ) +transpose(((transpose(X,-7) +transpose(transpose((((X+transpose(X,4) ) +transpose(X,7) ) |transpose(((X+transpose(X,4) ) +transpose(X,7) ) ,4) ) ,4) ,7) ) |(((X|X) +echo(arpeggio(X) ,4,6) ) +transpose(((X+transpose(X,12) ) |step(X,12) ) ,7) ) ) ,7) ) +transpose(((transpose(transpose(echo(transpose(X,-7) ,4,6) ,4) ,-5) +transpose(echo(transpose(transpose(shuffle(X) ,-7) ,-7) ,4,6) ,12) ) +transpose(arpeggio(step(echo((((X|X) +transpose(arpeggio(X) ,4) ) +transpose((X+transpose(X,7) ) ,7) ) ,4,6) ,12) ) ,12) ) ,7) ) ) ,4,6) |(transpose(((transpose((step(transpose(arpeggio(X) ,4) ,12) +X) ,4) |(((((transpose(X,-5) +transpose((X+X) ,7) ) +transpose(transpose(X,4) ,12) ) +transpose((transpose((X+X) ,4) |step(transpose(X,-7) ,12) ) ,4) ) +transpose((transpose(transpose(X,4) ,4) |(X+transpose(arpeggio(X) ,12) ) ) ,7) ) +transpose((shuffle(X) |shuffle(X) ) ,7) ) ) |(step(shuffle(arpeggio(transpose(X,4) ) ) ,12) |transpose(transpose(((echo(X,4,6) +transpose(X,12) ) |X) ,4) ,-7) ) ) ,4) +(transpose((shuffle(shuffle(transpose(echo(transpose(X,-5) ,4,6) ,-5) ) ) |step(echo((X+transpose(X,7) ) ,4,6) ,12) ) ,-7) |(echo(arpeggio((X+transpose(X,12) ) ) ,4,6) +transpose(transpose(((transpose((step(X,12) +transpose(X,12) ) ,-5) |transpose(shuffle(X) ,-7) ) +transpose(transpose(((X+X) +transpose((X+transpose(X,12) ) ,12) ) ,4) ,7) ) ,4) ,12) ) ) ) ) ,4,6) |step(step(((((transpose((arpeggio(X) +transpose(transpose(transpose(X,-5) ,-7) ,7) ) ,-7) |transpose(((transpose(transpose((X|X) ,4) ,-5) |(((X|X) +transpose(((X+transpose(X,4) ) +transpose(X,7) ) ,12) ) |step(transpose(((X+X) +transpose(X,12) ) ,-7) ,12) ) ) +transpose(step(echo((((X+transpose(X,7) ) +transpose(X,4) ) +transpose(X,7) ) ,4,6) ,12) ,12) ) ,-5) ) +transpose(((transpose(((((((X+transpose(X,4) ) +transpose(X,7) ) +transpose(X,12) ) +transpose(X,4) ) +transpose(transpose(X,4) ,7) ) +transpose(((X|(X+transpose(X,12) ) ) +transpose(arpeggio(echo(transpose(X,-7) ,4,6) ) ,12) ) ,12) ) ,4) +transpose(shuffle(((shuffle(X) +transpose(transpose((X+transpose(X,12) ) ,4) ,4) ) +transpose(((X|X) |X) ,7) ) ) ,7) ) |transpose(shuffle(arpeggio(echo(((X+transpose(X,4) ) +transpose(X,7) ) ,4,6) ) ) ,4) ) ,4) ) +transpose(transpose(((transpose((X+transpose(X,12) ) ,4) +transpose(transpose(X,-7) ,4) ) +transpose(transpose(step(X,12) ,-7) ,7) ) ,4) ,7) ) +transpose(transpose(transpose(transpose(step(((transpose((X|X) ,-5) +transpose(transpose((X+transpose(X,7) ) ,4) ,4) ) +transpose(X,7) ) ,12) ,-5) ,-7) ,4) ,7) ) ,12) ,12) )
random seed used was 0

NOTE: Generated phrase was too large ( 13188 ) , it has been truncated at 5000 notes. EXPR = transpose(((arpeggio(transpose(echo(((X+transpose(shuffle(X) ,7) ) +transpose((transpose(X,4) +transpose(X,12) ) ,12) ) ,4,6) ,-7) ) +transpose(step((((transpose((((((X+X) +transpose(((((X+transpose(X,4) ) +transpose(X,7) ) +transpose(X,4) ) +transpose(shuffle(X) ,7) ) ,7) ) +transpose(((arpeggio((X+transpose(X,12) ) ) +transpose(transpose((X+transpose(X,12) ) ,-5) ,12) ) +transpose(X,12) ) ,12) ) |transpose((shuffle(transpose(X,4) ) +step(echo(X,4,6) ,12) ) ,4) ) |transpose(transpose(transpose(X,4) ,4) ,4) ) ,-5) +transpose((echo((step(transpose(arpeggio(X) ,-7) ,12) +transpose(shuffle(transpose(((step(((X+transpose(X,4) ) +transpose(X,7) ) ,12) +transpose(transpose(step(X,12) ,4) ,4) ) +transpose(transpose(step(X,12) ,4) ,7) ) ,-5) ) ,12) ) ,4,6) |(echo((((transpose(X,4) |echo(X,4,6) ) +transpose((((transpose(X,4) +transpose((X+X) ,4) ) +transpose((X+X) ,7) ) |shuffle(X) ) ,4) ) +transpose((echo(X,4,6) +transpose((X+transpose(X,12) ) ,12) ) ,7) ) ,4,6) |step((((transpose(X,4) +((arpeggio(X) +transpose(transpose(X,-5) ,4) ) +transpose(X,7) ) ) |((X+transpose(X,-5) ) |echo(X,4,6) ) ) |(X+transpose(X,-7) ) ) ,12) ) ) ,12) ) +transpose(transpose(transpose(((transpose(X,-5) |transpose(X,-7) ) |(((X+X) +transpose(((transpose(shuffle((X+transpose(X,7) ) ) ,-7) +transpose(echo(step(transpose(X,-7) ,12) ,4,6) ,4) ) +transpose(transpose(transpose(X,-5) ,4) ,7) ) ,4) ) +transpose(((transpose(X,4) +transpose(X,4) ) +transpose(shuffle(X) ,7) ) ,7) ) ) ,-5) ,-7) ,12) ) |((transpose(((transpose(transpose(X,-7) ,-7) |((X+transpose((X|((transpose(X,4) +transpose(X,4) ) +transpose(X,7) ) ) ,4) ) +transpose((X|X) ,7) ) ) |step(transpose(((X|X) +transpose((X+transpose(X,12) ) ,12) ) ,4) ,12) ) ,-5) |echo(arpeggio(transpose((X|X) ,-5) ) ,4,6) ) +transpose(transpose(transpose(shuffle(transpose((X+transpose(X,7) ) ,4) ) ,-5) ,-5) ,7) ) ) ,12) ,4) ) +transpose(transpose(((arpeggio(transpose(transpose(transpose(step((shuffle(X) |arpeggio(transpose(X,4) ) ) ,12) ,4) ,4) ,4) ) +transpose((transpose((((X+transpose((transpose(X,-5) |transpose(X,-7) ) ,4) ) +transpose(echo(X,4,6) ,7) ) +transpose(X,7) ) ,-7) |transpose(((X+X) +transpose(X,-5) ) ,-7) ) ,4) ) +transpose(transpose(transpose(transpose((transpose(X,4) +transpose(((X+transpose(X,12) ) |echo(X,4,6) ) ,7) ) ,4) ,4) ,4) ,7) ) ,-5) ,7) ) ,4)
random seed used was 0 EXPR = transpose(transpose(arpeggio(transpose(echo(((shuffle(step(((transpose(X,-5) +transpose(((X|X) +transpose(X,7) ) ,4) ) +transpose(X,7) ) ,12) ) +transpose(echo(step((echo(X,4,6) |transpose((X+transpose(X,7) ) ,4) ) ,12) ,4,6) ,7) ) +(transpose((transpose(X,-7) +transpose(transpose(X,-7) ,12) ) ,4) +transpose(step(transpose((X|((X+transpose(X,4) ) +transpose(X,7) ) ) ,-5) ,12) ,12) ) ) ,4,6) ,4) ) ,-5) ,4)
random seed used was 0


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