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:
Randomize seed:
Generations:
Phrase for X:
# of Tracks:
Randomize patches:
 

Results may not appear for a few seconds.
Be patient!
Do you like this result? Do you want to let other people listen to it?

Save this one in the
Tune Trove!


See what's already
in the Tune Trove!

After 20 generations the expression "X" became this:
echo(((arpeggio((step(transpose(step(step(arpeggio(transpose(echo(arpeggio(transpose((X+transpose(X,12) ) ,4) ) ,4,6) ,-7) ) ,12) ,12) ,4) ,12) +transpose(step((transpose(shuffle((((((X+transpose(X,7) ) +transpose(shuffle(X) ,12) ) +transpose(transpose((transpose(X,-7) +transpose((X+X) ,7) ) ,-7) ,12) ) +transpose(echo(arpeggio(transpose(X,4) ) ,4,6) ,12) ) +transpose(echo((transpose(shuffle(transpose(arpeggio(X) ,-7) ) ,4) |(((echo(X,4,6) +transpose(echo(step(((X+transpose(X,4) ) +transpose(X,7) ) ,12) ,4,6) ,4) ) +transpose((X+transpose(X,-7) ) ,7) ) +transpose(step(echo(((X|X) +transpose(X,12) ) ,4,6) ,12) ,7) ) ) ,4,6) ,7) ) ) ,4) +((shuffle((transpose(arpeggio(arpeggio(X) ) ,4) +echo(transpose(transpose(X,-7) ,4) ,4,6) ) ) +transpose((transpose(shuffle((transpose(X,-7) |X) ) ,-7) +transpose(((transpose(step(X,12) ,-5) |shuffle(X) ) +transpose(step(transpose(X,-5) ,12) ,7) ) ,12) ) ,7) ) +(transpose(transpose(transpose(step(arpeggio((arpeggio(arpeggio(X) ) +transpose(echo(transpose(X,-5) ,4,6) ,7) ) ) ,12) ,-5) ,-7) ,-7) +transpose((((transpose(arpeggio(((arpeggio(X) +transpose(shuffle((X+transpose(X,12) ) ) ,7) ) |(echo(X,4,6) +transpose(transpose((X+transpose(X,12) ) ,-7) ,12) ) ) ) ,-7) |transpose(transpose(step(X,12) ,-5) ,-5) ) +transpose(arpeggio(echo(((transpose(transpose(X,-7) ,-7) +transpose(shuffle(X) ,4) ) +transpose(X,7) ) ,4,6) ) ,4) ) +transpose(transpose(step(((arpeggio(transpose(transpose(step(X,12) ,-7) ,-5) ) +transpose(((shuffle(X) +transpose(X,4) ) +transpose((X+transpose(X,12) ) ,7) ) ,4) ) +transpose(((X+transpose(X,12) ) +transpose(arpeggio(X) ,12) ) ,7) ) ,12) ,-7) ,7) ) ,12) ) ) ) ,12) ,12) ) ) +transpose((step(((((step(transpose(transpose((echo((step((X|X) ,12) +transpose(X,12) ) ,4,6) |transpose(echo(transpose((X+transpose(X,7) ) ,-7) ,4,6) ,-7) ) ,4) ,-5) ,12) +transpose((step(echo(shuffle(((X+transpose(X,4) ) +transpose(X,7) ) ) ,4,6) ,12) +transpose((X+transpose(X,7) ) ,4) ) ,12) ) +transpose((step(echo(transpose(step(echo(X,4,6) ,12) ,-5) ,4,6) ,12) +transpose(((transpose(transpose(transpose(transpose((shuffle(X) |X) ,4) ,-5) ,-5) ,-7) +transpose(transpose(transpose(((((transpose(X,-7) +transpose(shuffle(X) ,7) ) +transpose(step(transpose(X,4) ,12) ,7) ) +transpose(((X+transpose(X,12) ) |echo(X,4,6) ) ,4) ) +transpose((X+transpose(((transpose(X,4) +transpose(step((X+transpose(X,7) ) ,12) ,4) ) +transpose(((X+transpose((X|X) ,4) ) +transpose(transpose(X,-5) ,7) ) ,7) ) ,12) ) ,7) ) ,-5) ,-7) ,4) ) +transpose((((step((step(transpose(transpose(X,4) ,4) ,12) +transpose((X+transpose(X,7) ) ,7) ) ,12) +transpose(((step(((((X+transpose(X,12) ) +transpose(transpose(X,-5) ,4) ) +transpose(X,7) ) +transpose(transpose(X,-7) ,7) ) ,12) +transpose((arpeggio(arpeggio((X+transpose(X,7) ) ) ) +transpose(transpose(transpose(echo(X,4,6) ,4) ,4) ,7) ) ,4) ) +transpose((((((X+transpose(X,7) ) +transpose(X,4) ) +transpose(X,7) ) |((shuffle(X) +transpose(X,4) ) +transpose((X+transpose(X,12) ) ,7) ) ) +((X+X) +transpose((arpeggio(X) +transpose((X+X) ,12) ) ,12) ) ) ,7) ) ,4) ) +transpose(((step(transpose((((X+transpose(X,7) ) +transpose(X,4) ) +transpose(((X+transpose(X,4) ) +transpose(X,7) ) ,7) ) ,-7) ,12) +transpose(((transpose(transpose(X,-5) ,-7) +transpose((X|X) ,12) ) +transpose((((X+transpose(X,4) ) +transpose(X,7) ) |echo(step(X,12) ,4,6) ) ,12) ) ,12) ) +transpose(step((shuffle((echo(X,4,6) |(X|X) ) ) +transpose((X|X) ,12) ) ,12) ,7) ) ,7) ) +transpose(transpose(echo(transpose(transpose(X,-7) ,-7) ,4,6) ,4) ,12) ) ,7) ) ,7) ) ,12) ) +transpose((arpeggio(transpose(step(step((((transpose(echo(X,4,6) ,4) +transpose((step(X,12) |transpose(X,-5) ) ,4) ) +transpose((X+X) ,7) ) +transpose(echo((X|shuffle(X) ) ,4,6) ,7) ) ,12) ,12) ,4) ) +transpose(echo((((transpose(transpose((((arpeggio(X) +transpose(step(X,12) ,7) ) +transpose(step(arpeggio(X) ,12) ,12) ) +(step(transpose(X,-7) ,12) +transpose(echo(transpose(X,-7) ,4,6) ,12) ) ) ,4) ,-7) +transpose(transpose(transpose((arpeggio(shuffle((X+transpose(X,7) ) ) ) +transpose(transpose(transpose(arpeggio(shuffle(X) ) ,4) ,-7) ,12) ) ,-7) ,-5) ,4) ) +transpose(((echo(X,4,6) +((X+transpose(X,12) ) +transpose(step(step(X,12) ,12) ,12) ) ) |echo(shuffle(step((echo(X,4,6) +transpose(shuffle(X) ,12) ) ,12) ) ,4,6) ) ,7) ) +transpose(((transpose((((transpose(arpeggio(X) ,-7) +transpose(transpose(transpose(transpose(X,-5) ,-5) ,-5) ,4) ) +transpose(step(arpeggio(X) ,12) ,7) ) +transpose(shuffle((step((step(transpose(X,-7) ,12) +transpose((X+transpose(X,12) ) ,12) ) ,12) +((X+transpose(X,12) ) +transpose(X,7) ) ) ) ,7) ) ,-7) +transpose(step(transpose(((((((echo(X,4,6) +transpose(X,4) ) +transpose(arpeggio(X) ,7) ) +step(X,12) ) +transpose(((step(shuffle(X) ,12) +transpose((X+X) ,4) ) +transpose(echo(echo(X,4,6) ,4,6) ,7) ) ,4) ) +transpose((transpose(X,4) +transpose((X+transpose(X,12) ) ,7) ) ,7) ) |(transpose(X,-7) +(((echo(X,4,6) +transpose(step(X,12) ,4) ) +transpose(transpose(X,-7) ,7) ) +transpose(shuffle(echo(X,4,6) ) ,12) ) ) ) ,-7) ,12) ,4) ) +transpose(echo(shuffle(shuffle((((shuffle(X) |X) +transpose(X,7) ) +transpose((transpose((X+transpose(X,7) ) ,-7) +transpose(transpose(X,-5) ,12) ) ,12) ) ) ) ,4,6) ,7) ) ,7) ) ,4,6) ,7) ) ,7) ) +transpose(((((step(arpeggio(arpeggio(transpose(((step(echo(((X+transpose(X,4) ) +transpose(X,7) ) ,4,6) ,12) +transpose(transpose(transpose(X,4) ,-7) ,12) ) +transpose(X,-7) ) ,-7) ) ) ,12) +transpose(transpose(echo(((((transpose(transpose(transpose(X,-7) ,4) ,4) |transpose(shuffle(transpose(X,-7) ) ,-7) ) |(transpose(echo(arpeggio(X) ,4,6) ,-5) +transpose((X|echo((((X+transpose(X,7) ) +transpose(X,4) ) +transpose(transpose(X,-7) ,7) ) ,4,6) ) ,7) ) ) +transpose(arpeggio(transpose(((X+transpose(X,7) ) +transpose(transpose(X,-7) ,-5) ) ,-7) ) ,4) ) +transpose(shuffle((echo(shuffle(echo(((X+transpose(X,4) ) +transpose(X,7) ) ,4,6) ) ,4,6) +transpose((arpeggio(arpeggio(transpose(X,-7) ) ) +transpose((arpeggio(X) +transpose(X,7) ) ,12) ) ,7) ) ) ,7) ) ,4,6) ,-7) ,12) ) |transpose(transpose((((((((transpose(transpose((X+X) ,-7) ,-7) +step(echo(arpeggio(X) ,4,6) ,12) ) +transpose(transpose((((arpeggio(X) +transpose(X,12) ) +transpose((arpeggio(X) |step(X,12) ) ,12) ) +(((X|X) |transpose(X,-7) ) +transpose(((X+transpose(X,4) ) +transpose(X,7) ) ,7) ) ) ,4) ,4) ) +transpose(arpeggio(step(transpose(shuffle(X) ,-7) ,12) ) ,7) ) +transpose(step((((((X+X) +transpose((X|X) ,12) ) |transpose(X,-7) ) +transpose(transpose(echo(transpose(X,-7) ,4,6) ,4) ,4) ) +transpose((step(transpose(X,-5) ,12) +transpose(((step(X,12) +transpose(echo(X,4,6) ,4) ) +transpose((X|X) ,7) ) ,12) ) ,7) ) ,12) ,4) ) +transpose((((shuffle(X) +transpose(((X+transpose(echo(X,4,6) ,12) ) +transpose((transpose(X,-7) +transpose((X|X) ,7) ) ,12) ) ,7) ) +transpose((arpeggio((X+transpose(X,7) ) ) +transpose(transpose(((X+transpose(X,4) ) +transpose(X,7) ) ,-7) ,12) ) ,7) ) +transpose(transpose(X,-7) ,7) ) ,7) ) |shuffle((transpose((((step(X,12) +transpose(X,12) ) +transpose(arpeggio(transpose(X,-5) ) ,7) ) +transpose((((echo(X,4,6) +transpose((X+transpose(X,12) ) ,12) ) +transpose(step((X+transpose(X,7) ) ,12) ,4) ) +transpose(X,7) ) ,12) ) ,-5) |shuffle(step((((X+transpose(X,7) ) +transpose(transpose(X,-5) ,4) ) +transpose(X,7) ) ,12) ) ) ) ) |arpeggio(((transpose(echo((transpose(X,-7) +transpose(arpeggio(X) ,7) ) ,4,6) ,-7) +transpose(transpose(shuffle((arpeggio((X+transpose(X,7) ) ) |(transpose(X,-7) +transpose(X,12) ) ) ) ,-5) ,4) ) +transpose(transpose(transpose(transpose(X,-7) ,4) ,-5) ,7) ) ) ) ,4) ,4) ) +transpose(transpose(((transpose(((step((X|((echo(X,4,6) +transpose(X,12) ) +echo(transpose(echo(X,4,6) ,-7) ,4,6) ) ) ,12) +transpose(arpeggio(shuffle(((echo(step(X,12) ,4,6) +transpose(transpose((shuffle(X) |X) ,-7) ,4) ) +transpose(shuffle(((X+transpose(X,4) ) +transpose(X,7) ) ) ,7) ) ) ) ,4) ) +transpose(transpose((transpose(step(echo(transpose((X|X) ,4) ,4,6) ,12) ,4) +((X+shuffle(X) ) +transpose(step((X+transpose(X,7) ) ,12) ,12) ) ) ,-7) ,7) ) ,-7) +transpose(((transpose((shuffle(arpeggio(arpeggio((X+transpose(transpose((X+X) ,-5) ,7) ) ) ) ) |echo(shuffle(echo(((X+transpose(((X+transpose(X,4) ) +transpose(X,7) ) ,7) ) +transpose(arpeggio(((X+transpose(X,4) ) +transpose(X,7) ) ) ,-7) ) ,4,6) ) ,4,6) ) ,-7) +transpose(arpeggio(arpeggio((transpose((transpose(shuffle(X) ,4) +(X+transpose(step(X,12) ,7) ) ) ,-5) +transpose((transpose((transpose(step(X,12) ,-7) |(X|X) ) ,-7) |step(X,12) ) ,12) ) ) ) ,7) ) +transpose((arpeggio(arpeggio((((X|transpose(X,-7) ) +transpose(((((X+X) +transpose(((X+transpose(X,4) ) +transpose(X,7) ) ,7) ) +transpose(X,7) ) +transpose(transpose(echo(X,4,6) ,-7) ,12) ) ,4) ) +transpose(arpeggio(echo(arpeggio(transpose(X,-5) ) ,4,6) ) ,7) ) ) ) +transpose(transpose(echo(transpose(transpose((transpose(X,4) +transpose(echo(X,4,6) ,12) ) ,-7) ,-7) ,4,6) ,-5) ,7) ) ,7) ) ,4) ) +transpose(step((((((transpose(X,4) +transpose((X+transpose(X,7) ) ,4) ) +transpose((X+(X+transpose(X,12) ) ) ,7) ) +transpose(transpose((((transpose(((X|X) +transpose(X,4) ) ,-5) +transpose(((X|X) +X) ,7) ) +transpose((arpeggio(transpose(X,-7) ) +transpose(arpeggio(transpose(transpose(X,-7) ,-7) ) ,12) ) ,4) ) +transpose(echo((X+X) ,4,6) ,7) ) ,-7) ,4) ) +transpose(step(step(transpose(X,4) ,12) ,12) ,7) ) +((((transpose(((X+transpose(X,12) ) +transpose(X,-7) ) ,-7) +(transpose(step(X,12) ,-5) +transpose(arpeggio(((X+transpose(X,4) ) +transpose(X,7) ) ) ,12) ) ) +transpose(transpose(echo(shuffle((X+transpose(X,7) ) ) ,4,6) ,-7) ,4) ) +transpose(transpose(arpeggio((X+transpose(X,7) ) ) ,4) ,7) ) +transpose(((echo(transpose(X,-7) ,4,6) +transpose(step(arpeggio(X) ,12) ,12) ) +transpose(((shuffle(transpose(X,-5) ) +transpose(((X+transpose(X,7) ) +(X+transpose(X,12) ) ) ,4) ) +transpose((transpose(X,4) +transpose(X,12) ) ,7) ) ,4) ) ,7) ) ) ,12) ,7) ) ,-7) ,4) ) +transpose((((((echo((((((shuffle(((step(X,12) +transpose(X,4) ) +transpose(X,7) ) ) +transpose(((transpose(X,-7) +transpose(X,7) ) +transpose(transpose(X,-7) ,7) ) ,4) ) +transpose(((arpeggio(transpose(X,4) ) +transpose((X+X) ,4) ) +transpose(step(X,12) ,7) ) ,7) ) +transpose(shuffle(transpose(((echo(X,4,6) +transpose(shuffle(X) ,12) ) +transpose((X|X) ,7) ) ,-7) ) ,4) ) +transpose(((transpose(transpose(X,-7) ,-5) +transpose(X,4) ) +transpose(((shuffle(transpose(X,-7) ) +transpose(echo(X,4,6) ,4) ) +transpose(((X+transpose(X,12) ) |echo(X,4,6) ) ,7) ) ,4) ) ,7) ) |(((X+transpose(step(X,12) ,7) ) +transpose(echo((X+transpose((X+transpose(X,12) ) ,7) ) ,4,6) ,4) ) +transpose(((((X+transpose(X,7) ) |X) +transpose(arpeggio(X) ,4) ) +transpose((X+step((X|transpose(X,-7) ) ,12) ) ,7) ) ,7) ) ) ,4,6) +transpose(transpose(echo(transpose(((arpeggio(X) |transpose(X,-7) ) +transpose(arpeggio(X) ,7) ) ,-5) ,4,6) ,-7) ,7) ) +transpose((arpeggio(transpose(echo(echo(transpose(arpeggio(X) ,-5) ,4,6) ,4,6) ,4) ) +transpose(transpose(transpose(transpose(transpose(transpose(X,-7) ,-7) ,4) ,4) ,-7) ,7) ) ,4) ) +transpose(transpose(transpose(transpose(((step(X,12) +transpose(echo(transpose(X,-5) ,4,6) ,4) ) +transpose((arpeggio(X) +transpose(arpeggio(X) ,12) ) ,7) ) ,4) ,4) ,4) ,7) ) +transpose((transpose((arpeggio((echo(transpose(X,-7) ,4,6) +(X|X) ) ) +transpose(((transpose(transpose((X+transpose(step(X,12) ,7) ) ,-7) ,-7) +transpose(step(((echo(X,4,6) +(X+transpose(X,12) ) ) +(((X+transpose(X,4) ) +transpose(X,7) ) +transpose((X+X) ,7) ) ) ,12) ,4) ) +transpose((X|transpose(arpeggio(X) ,-7) ) ,7) ) ,12) ) ,-7) +transpose((transpose(transpose((transpose(shuffle(X) ,-5) +transpose(((transpose(X,-5) +transpose(transpose(X,-7) ,7) ) +transpose(transpose(arpeggio(X) ,-7) ,12) ) ,12) ) ,-7) ,-7) +transpose(transpose(transpose(step(((shuffle(step((arpeggio(X) +transpose(echo(X,4,6) ,7) ) ,12) ) +transpose(((((X+transpose(X,12) ) +transpose(transpose(X,-7) ,7) ) +transpose((transpose(X,-5) |shuffle((X+transpose(X,12) ) ) ) ,12) ) +transpose(shuffle(transpose(((X+transpose(X,4) ) +transpose(X,7) ) ,-5) ) ,7) ) ,4) ) +transpose((transpose(arpeggio(transpose(step(X,12) ,-7) ) ,-5) +((shuffle(arpeggio((X+transpose(X,7) ) ) ) +transpose((X+X) ,4) ) +transpose(transpose(transpose(X,4) ,-7) ,7) ) ) ,7) ) ,12) ,-7) ,-5) ,12) ) ,12) ) ,4) ) +transpose(step(arpeggio((transpose(((X+transpose(shuffle(X) ,4) ) +transpose(X,7) ) ,4) +transpose(echo((transpose(X,-5) +transpose(((X+transpose(X,4) ) +transpose(X,7) ) ,7) ) ,4,6) ,12) ) ) ,12) ,7) ) ,7) ) ,-7) ) ,12) +((transpose(echo(transpose(step(((((echo((((X+transpose(X,4) ) +transpose(X,7) ) +transpose(((X+transpose(X,4) ) +transpose(X,7) ) ,12) ) ,4,6) +transpose((transpose(step((X|X) ,12) ,-7) |transpose(transpose(((shuffle(X) +transpose(shuffle(X) ,4) ) +transpose(X,7) ) ,-5) ,4) ) ,-5) ) +transpose(((shuffle((transpose(transpose(echo((X+transpose(X,12) ) ,4,6) ,-5) ,-7) +transpose(echo(shuffle(transpose(X,-7) ) ,4,6) ,12) ) ) +transpose(((transpose(step(transpose(arpeggio(X) ,-7) ,12) ,-5) +transpose(transpose(echo(transpose(step(X,12) ,-7) ,4,6) ,-7) ,7) ) |arpeggio(step(X,12) ) ) ,4) ) +transpose(transpose((transpose((X+X) ,-5) +transpose((X+X) ,12) ) ,-7) ,7) ) ,7) ) +transpose(arpeggio(transpose((((step(X,12) +transpose((X+transpose(X,12) ) ,12) ) +transpose((transpose(X,-7) +transpose(X,12) ) ,4) ) +transpose(((X|X) +transpose(step(X,12) ,7) ) ,7) ) ,4) ) ,4) ) +transpose((step(transpose(step((transpose(transpose(transpose(X,4) ,-7) ,4) +transpose((transpose((X+transpose(X,7) ) ,-7) +transpose(X,12) ) ,7) ) ,12) ,-7) ,12) +transpose(((echo(((((X+transpose(((X+transpose(X,4) ) +transpose(X,7) ) ,4) ) +transpose(X,7) ) +transpose(X,4) ) +transpose(arpeggio(step(X,12) ) ,7) ) ,4,6) +arpeggio(shuffle((X+transpose(transpose(X,-5) ,12) ) ) ) ) +transpose(echo(transpose(X,-7) ,4,6) ,12) ) ,7) ) ,7) ) ,12) ,4) ,4,6) ,4) +transpose((echo(((transpose((shuffle((X+transpose(X,7) ) ) +transpose(step(X,12) ,12) ) ,-7) +transpose((step(transpose(echo((transpose(step(X,12) ,4) |(shuffle(X) +transpose(X,7) ) ) ,4,6) ,4) ,12) +transpose(transpose((transpose((((shuffle(X) +transpose(transpose((X+transpose(transpose(X,-5) ,12) ) ,-7) ,4) ) +transpose(transpose((X+transpose(X,12) ) ,-7) ,7) ) +transpose(echo(X,4,6) ,12) ) ,4) +transpose((transpose((X+transpose(step(X,12) ,12) ) ,-7) +(step(transpose(echo(X,4,6) ,-7) ,12) +transpose((transpose((X|X) ,4) +transpose(X,7) ) ,4) ) ) ,4) ) ,4) ,12) ) ,4) ) +transpose(((transpose(arpeggio((((transpose((X+X) ,-5) +transpose(arpeggio(shuffle(X) ) ,12) ) +transpose(echo(shuffle((X+transpose(X,7) ) ) ,4,6) ,12) ) +transpose(((transpose(((X+transpose(X,4) ) +transpose(X,7) ) ,-5) +transpose(((arpeggio(X) +transpose(arpeggio(X) ,4) ) +transpose(X,7) ) ,12) ) +step(((step(X,12) +transpose(X,4) ) +transpose(step(X,12) ,7) ) ,12) ) ,7) ) ) ,4) +transpose(step((((X+transpose((transpose(X,-7) +transpose(transpose(X,-7) ,7) ) ,7) ) +transpose(transpose(((X+transpose(X,4) ) +transpose(X,7) ) ,-7) ,12) ) +step((X+((X+transpose(X,4) ) +transpose(X,7) ) ) ,12) ) ,12) ,4) ) +transpose(shuffle((((step(transpose((transpose(echo(X,4,6) ,-7) +transpose(transpose((arpeggio(X) +transpose((X+transpose(X,7) ) ,7) ) ,4) ,12) ) ,-5) ,12) +transpose(transpose(shuffle(echo((transpose(X,-7) +transpose(transpose(X,-7) ,12) ) ,4,6) ) ,-7) ,7) ) +transpose(((transpose(((X+X) +(X+transpose(X,12) ) ) ,-7) +transpose(step((transpose(transpose(X,-5) ,-5) +transpose(transpose(transpose(X,-5) ,4) ,7) ) ,12) ,7) ) |(step(X,12) +transpose((((X+transpose(X,7) ) +transpose(X,4) ) +transpose(X,7) ) ,12) ) ) ,4) ) +transpose((echo((((X+transpose(X,7) ) +transpose(X,7) ) +transpose((echo(X,4,6) +transpose(arpeggio(echo(X,4,6) ) ,7) ) ,12) ) ,4,6) +(transpose(((shuffle(X) +transpose(echo(transpose(X,-5) ,4,6) ,4) ) +transpose(shuffle((transpose(X,-5) +transpose(X,12) ) ) ,7) ) ,-7) +(step(X,12) +transpose(X,12) ) ) ) ,7) ) ) ,7) ) ,7) ) ,4,6) |arpeggio(arpeggio(transpose(((transpose(transpose(((step(X,12) +transpose(step(transpose(X,-7) ,12) ,4) ) +transpose(((((X+transpose(X,4) ) +transpose(X,7) ) +transpose((X+transpose(X,12) ) ,4) ) +transpose(X,7) ) ,7) ) ,4) ,4) +transpose(shuffle((X+transpose((X+transpose(arpeggio(X) ,7) ) ,12) ) ) ,4) ) +transpose((shuffle(X) +transpose(((((X+transpose((X+transpose(X,12) ) ,4) ) +transpose(transpose(X,-7) ,7) ) +transpose(arpeggio(transpose(transpose(X,-7) ,-7) ) ,12) ) +transpose((shuffle(X) +transpose(transpose(X,-7) ,12) ) ,-7) ) ,7) ) ,7) ) ,-5) ) ) ) ,4) ) +transpose((((step(shuffle(transpose(step(step(((transpose(X,-7) +(X+transpose(X,7) ) ) +transpose(step((((echo(X,4,6) +transpose(arpeggio(X) ,12) ) +transpose(transpose((X+transpose(X,7) ) ,4) ,4) ) +transpose(transpose(X,-5) ,7) ) ,12) ,12) ) ,12) ,12) ,4) ) ,12) +transpose((echo(((transpose((transpose(X,4) +transpose((X+transpose(X,7) ) ,-7) ) ,4) +transpose(step(transpose((echo(echo((X+transpose(arpeggio(X) ,7) ) ,4,6) ,4,6) |echo(X,4,6) ) ,-7) ,12) ,4) ) +transpose((echo((((X+transpose(X,12) ) +transpose(transpose(X,-7) ,7) ) +echo(transpose(X,4) ,4,6) ) ,4,6) +transpose(arpeggio(transpose(((X+transpose(transpose(X,-5) ,7) ) +transpose((shuffle((X|X) ) +transpose(transpose(transpose(X,-5) ,-7) ,12) ) ,7) ) ,4) ) ,12) ) ,7) ) ,4,6) +transpose(transpose((((transpose(((X+transpose(X,4) ) +transpose(X,7) ) ,-7) +transpose((X+X) ,4) ) +transpose(step(step(X,12) ,12) ,7) ) +transpose((((X+X) +transpose(echo((X+transpose(X,7) ) ,4,6) ,12) ) +(X+transpose((X|X) ,7) ) ) ,12) ) ,-7) ,12) ) ,12) ) +transpose((transpose(transpose(step((((X+transpose(transpose(X,-5) ,7) ) +transpose(X,-5) ) +transpose(((((arpeggio(transpose(X,-5) ) +transpose(step(transpose(X,-7) ,12) ,-7) ) |(transpose((X+transpose(X,12) ) ,-7) +transpose((((X+transpose(X,4) ) +transpose(X,7) ) |transpose(X,-5) ) ,7) ) ) +transpose(shuffle(arpeggio((echo((X+transpose(X,7) ) ,4,6) |((X+transpose(X,7) ) +transpose(arpeggio(X) ,7) ) ) ) ) ,4) ) +transpose(arpeggio(transpose(transpose(((((X+transpose(X,4) ) +transpose(X,7) ) +transpose(shuffle(((X+transpose(X,4) ) +transpose(X,7) ) ) ,4) ) +transpose(arpeggio(X) ,7) ) ,-7) ,-7) ) ,7) ) ,7) ) ,12) ,-5) ,-7) +echo((((((step(X,12) +transpose(shuffle(arpeggio(X) ) ,4) ) +transpose(transpose((X+transpose(X,12) ) ,-5) ,7) ) +step((arpeggio(X) +transpose(shuffle(X) ,12) ) ,12) ) +(echo(transpose(X,4) ,4,6) +transpose(shuffle(shuffle(X) ) ,7) ) ) +transpose(transpose(step((transpose(X,-5) +transpose(step((X+transpose(X,12) ) ,12) ,7) ) ,12) ,4) ,7) ) ,4,6) ) ,12) ) +transpose((transpose(step(((((transpose(((((arpeggio(X) +transpose(X,7) ) +arpeggio(((X+transpose(X,7) ) +transpose(X,7) ) ) ) +transpose(transpose(transpose(transpose(X,-7) ,-7) ,-7) ,4) ) +transpose((step((X+transpose((X+transpose(X,7) ) ,12) ) ,12) +(shuffle(((X+transpose(X,4) ) +transpose(X,7) ) ) +shuffle(X) ) ) ,7) ) ,-5) +transpose(step(step(((((arpeggio(X) +transpose(echo(X,4,6) ,4) ) +transpose(shuffle(X) ,7) ) +transpose(transpose(transpose((X+transpose(X,7) ) ,-7) ,-7) ,7) ) +transpose((shuffle((X+transpose(X,7) ) ) +transpose(((X|X) +transpose((X+transpose(X,7) ) ,12) ) ,7) ) ,12) ) ,12) ,12) ,4) ) +transpose(step(((((transpose(shuffle(transpose(X,-7) ) ,-7) +transpose(((step(echo(((X+transpose(X,4) ) +transpose(X,7) ) ,4,6) ,12) +transpose(((transpose((X+transpose(X,7) ) ,-7) +transpose((echo(X,4,6) +transpose(transpose(X,-7) ,12) ) ,4) ) +transpose(transpose(X,4) ,7) ) ,4) ) +transpose(transpose(((X+transpose(X,12) ) |X) ,-5) ,7) ) ,4) ) +transpose(transpose(arpeggio((X+X) ) ,-7) ,7) ) +transpose(((((((transpose(transpose(shuffle(X) ,-7) ,4) +transpose(((transpose(X,4) +transpose(arpeggio(X) ,12) ) +transpose(transpose((X+transpose(X,7) ) ,4) ,7) ) ,4) ) +transpose(echo(X,4,6) ,7) ) +transpose((transpose((X+transpose(transpose(X,-7) ,7) ) ,-7) +transpose(transpose((((X+transpose(X,7) ) +transpose(X,4) ) +transpose(X,7) ) ,4) ,7) ) ,4) ) +transpose(transpose(transpose((((X+transpose(X,4) ) +transpose(X,7) ) +X) ,-7) ,-7) ,7) ) +transpose(transpose(echo(((((X+transpose(X,4) ) +transpose(X,7) ) +transpose(transpose(X,-7) ,4) ) +transpose(arpeggio(X) ,7) ) ,4,6) ,-7) ,4) ) +transpose(shuffle(transpose((X+transpose(X,12) ) ,4) ) ,7) ) ,4) ) +transpose(echo(((((X+transpose(X,12) ) +transpose(X,4) ) +transpose(transpose(X,4) ,7) ) +transpose((echo(X,4,6) +transpose(arpeggio(X) ,12) ) ,12) ) ,4,6) ,7) ) ,12) ,7) ) +transpose(transpose(((shuffle((((((X+transpose(X,4) ) +transpose(X,7) ) +transpose((X+transpose(X,7) ) ,4) ) +transpose(transpose(X,-7) ,7) ) +shuffle(X) ) ) +transpose((shuffle((transpose(arpeggio(X) ,4) +transpose(step(arpeggio(X) ,12) ,7) ) ) +transpose(transpose(X,-7) ,12) ) ,7) ) +transpose(transpose((arpeggio((X+transpose(X,7) ) ) +transpose((echo(shuffle(X) ,4,6) |step(X,12) ) ,12) ) ,4) ,12) ) ,-5) ,12) ) +transpose(transpose(step((echo(echo(transpose(transpose(X,4) ,4) ,4,6) ,4,6) +transpose(((transpose(arpeggio((X+transpose(X,7) ) ) ,-5) +transpose(step(echo(transpose(shuffle(X) ,-7) ,4,6) ,12) ,4) ) +transpose((transpose(X,-5) +transpose(transpose(((X+transpose(X,4) ) +transpose(X,7) ) ,-5) ,7) ) ,7) ) ,12) ) ,12) ,-7) ,7) ) ,12) ,-7) +((((arpeggio(transpose(arpeggio((((X+X) +transpose(step(X,12) ,12) ) +transpose(transpose(echo(X,4,6) ,-7) ,12) ) ) ,-7) ) +transpose(transpose(((transpose(step(((X+transpose(X,4) ) +transpose(X,7) ) ,12) ,-7) +transpose(shuffle(arpeggio((X+X) ) ) ,7) ) +transpose(((transpose(transpose(((((X+transpose(transpose(X,-7) ,4) ) +transpose((X+transpose(X,12) ) ,7) ) +X) |shuffle(X) ) ,4) ,4) +transpose(transpose(((echo(((((X+transpose(X,7) ) +transpose(X,12) ) +X) |X) ,4,6) +transpose(transpose(echo(X,4,6) ,-7) ,4) ) +transpose(transpose(echo((echo(X,4,6) +transpose(X,7) ) ,4,6) ,-5) ,7) ) ,-7) ,4) ) +transpose(transpose((X|arpeggio(X) ) ,-7) ,7) ) ,7) ) ,-7) ,4) ) +transpose(transpose(echo(echo((transpose((((X|X) +transpose(arpeggio((X|X) ) ,4) ) +transpose(transpose((X+transpose(X,7) ) ,4) ,7) ) ,-5) |(X+transpose((transpose(X,4) +transpose(step(X,12) ,12) ) ,12) ) ) ,4,6) ,4,6) ,-7) ,7) ) +transpose(((transpose(transpose(arpeggio((transpose(((X+transpose(X,7) ) +transpose(X,-7) ) ,-7) +transpose(((((transpose(X,4) +transpose(((X+transpose(X,4) ) +transpose(X,7) ) ,12) ) +transpose(step((X+transpose(X,12) ) ,12) ,12) ) +transpose(transpose(echo(transpose(transpose(X,-7) ,-7) ,4,6) ,4) ,4) ) +transpose((((X+transpose(X,7) ) +transpose(transpose(X,-7) ,7) ) +transpose(echo(transpose(X,-5) ,4,6) ,12) ) ,7) ) ,12) ) ) ,4) ,-7) +transpose((transpose((step(arpeggio(arpeggio((arpeggio(X) |(transpose(X,-5) +transpose(((X+transpose(X,4) ) +transpose(X,7) ) ,7) ) ) ) ) ,12) +transpose(shuffle((X|transpose(X,4) ) ) ,12) ) ,4) |step(step(transpose((((((X|X) +transpose(transpose(X,-7) ,7) ) |(((X|X) +transpose(((X+transpose(X,4) ) +transpose(X,7) ) ,12) ) +transpose((X+transpose(X,12) ) ,4) ) ) +transpose(transpose(step((((X+X) +transpose(X,4) ) +transpose((X+transpose(X,7) ) ,7) ) ,12) ,-7) ,4) ) +transpose((((transpose(X,-7) |X) +(X+transpose(X,4) ) ) +transpose((echo(arpeggio((X+transpose(X,12) ) ) ,4,6) +transpose(step(arpeggio(X) ,12) ,7) ) ,7) ) ,7) ) ,-7) ,12) ,12) ) ,4) ) +transpose(transpose(echo(((transpose(transpose(X,-7) ,-7) +transpose((step(((((X+transpose(transpose(X,-7) ,7) ) +transpose(X,12) ) +transpose(arpeggio(echo(transpose(X,-7) ,4,6) ) ,4) ) +transpose((((X+transpose(((X+transpose(X,4) ) +transpose(X,7) ) ,7) ) +transpose(step(X,12) ,4) ) +transpose(shuffle(X) ,7) ) ,7) ) ,12) +((echo(transpose(echo(((X+transpose(((X+transpose(X,4) ) +transpose(X,7) ) ,4) ) +transpose(((X+transpose(X,4) ) +transpose(X,7) ) ,7) ) ,4,6) ,-7) ,4,6) +transpose(((shuffle(step(X,12) ) |transpose((((X|X) +transpose(((X+transpose(X,4) ) +transpose(X,7) ) ,4) ) +transpose(shuffle(X) ,7) ) ,-5) ) +step(X,12) ) ,4) ) +transpose(shuffle(shuffle(echo(X,4,6) ) ) ,7) ) ) ,4) ) +transpose(arpeggio(((transpose(shuffle(((X+transpose(X,4) ) +transpose(X,7) ) ) ,-7) +shuffle((transpose(arpeggio(X) ,-7) +transpose(step(X,12) ,12) ) ) ) +transpose((arpeggio(X) +X) ,7) ) ) ,7) ) ,4,6) ,-7) ,7) ) ,12) ) +transpose(transpose(shuffle(transpose(transpose(echo(echo((((shuffle(((X+transpose(X,4) ) +transpose(X,7) ) ) +step((X+transpose(X,12) ) ,12) ) +transpose((arpeggio(arpeggio(X) ) +transpose(step(X,12) ,12) ) ,7) ) +transpose((shuffle(X) |shuffle(X) ) ,12) ) ,4,6) ,4,6) ,-7) ,-7) ) ,-7) ,12) ) ) ,12) ) ,7) ) ) ,4) ) +transpose((transpose(transpose(arpeggio(shuffle(transpose((transpose(arpeggio(((transpose(((arpeggio((X+transpose(X,12) ) ) +transpose((((X+transpose(X,4) ) +transpose(X,7) ) +transpose((X+transpose(X,12) ) ,12) ) ,4) ) +transpose((X+transpose(echo(X,4,6) ,12) ) ,7) ) ,-7) +transpose(step(step(X,12) ,12) ,4) ) +transpose(transpose((transpose(step(X,12) ,-7) +((X+X) |(X|X) ) ) ,-5) ,7) ) ) ,-7) +transpose(shuffle(((step((X+transpose(((X+transpose(X,12) ) +(X+transpose(X,12) ) ) ,7) ) ,12) +transpose(((X+transpose(X,12) ) |arpeggio(X) ) ,7) ) +transpose(arpeggio(transpose((transpose(X,-5) |(X+X) ) ,-5) ) ,12) ) ) ,7) ) ,-7) ) ) ,-7) ,-7) +transpose(echo(echo((shuffle(transpose((((((((((X|X) +transpose(X,4) ) +transpose(X,7) ) +transpose(((step(X,12) +transpose(step(X,12) ,4) ) +transpose((X+transpose(X,12) ) ,7) ) ,4) ) +transpose(step((X+transpose(X,7) ) ,12) ,7) ) +echo(step(arpeggio(X) ,12) ,4,6) ) +(shuffle((transpose(shuffle(X) ,-7) +transpose(X,12) ) ) +transpose(arpeggio(echo(arpeggio(X) ,4,6) ) ,12) ) ) +transpose(echo((step(transpose((X+X) ,4) ,12) +transpose((shuffle(transpose((X+X) ,-7) ) |transpose(arpeggio(shuffle(X) ) ,-7) ) ,7) ) ,4,6) ,4) ) +transpose((transpose(((X+transpose(X,4) ) +transpose(X,7) ) ,-7) +transpose((((((X+transpose((echo(transpose(X,4) ,4,6) +transpose((X+X) ,12) ) ,4) ) +transpose(shuffle(arpeggio(echo(X,4,6) ) ) ,7) ) +transpose(transpose((transpose(X,-7) +transpose(step(arpeggio(X) ,12) ,12) ) ,-7) ,4) ) +transpose(transpose((shuffle(step(X,12) ) +echo(X,4,6) ) ,4) ,7) ) +transpose(step(echo((X+transpose(X,12) ) ,4,6) ,12) ,7) ) ,12) ) ,7) ) ,-7) ) +transpose(((transpose((transpose(((transpose((X+transpose(X,12) ) ,-7) +X) |step(echo(X,4,6) ,12) ) ,-7) |echo(transpose(transpose((transpose(X,-5) |echo(echo(X,4,6) ,4,6) ) ,-7) ,-7) ,4,6) ) ,-5) +transpose(shuffle(((((step(transpose(X,-7) ,12) +transpose(shuffle(((shuffle(X) +transpose(step(X,12) ,4) ) +transpose(transpose(X,-7) ,7) ) ) ,7) ) +transpose(echo(step(((X+X) +transpose((X+X) ,7) ) ,12) ,4,6) ,4) ) +transpose((shuffle(arpeggio(X) ) |X) ,7) ) +((step(X,12) +((X+transpose(X,4) ) +transpose(X,7) ) ) +transpose(((shuffle(X) +transpose((X|shuffle(X) ) ,12) ) +step(X,12) ) ,12) ) ) ) ,4) ) +transpose((echo(arpeggio((echo(transpose(X,4) ,4,6) +transpose(arpeggio(X) ,12) ) ) ,4,6) +transpose(step((transpose((transpose(transpose(X,-7) ,4) +transpose((transpose(X,-7) +transpose((X+transpose(X,7) ) ,7) ) ,12) ) ,-5) |((transpose(arpeggio(X) ,4) +transpose(X,4) ) +transpose(transpose(X,-7) ,7) ) ) ,12) ,12) ) ,7) ) ,12) ) ,4,6) ,4,6) ,-7) ) ,7) ) ,4,6)
random seed used was 153858450

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