In fact, they are generated by an incredibly simple little formula, and are thus completely regular and repeatable, like the tunes of a cheap pianola. However, the music will be highly dependent on from where it starts. You can manipulate the digits in the formula, and Debussy, still manic, will be heard running off into some totally unmapped region of the cosmos of boring melodies. This is what is meant by chaos. The smallest change in initial values will grow beyond recognition.
People sometimes find it hard to see the difference between chaos and randomness.
They are remarkably good at discerning patterns, and chaotic processes often contain more of it than the word makes You expect. Your computer will calculate a numerical value from the formula, and then put it back into the same formula as a new value of x. If You make any change in the value of r You will get a new melody, if that is what one should call it. This is a completely innocent little application, which won't do any evil things to Your computer. You'll need QuickTime to get any sound at all.