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.
| After 2 generations the expression "X" became this: |
| X random seed used was 164051968 |
The algorithm for Expresso is written in
KeyKit, and
here's the source code.