Here are tips & tricks for frank's cellular automaton music program.

You can add a note to the color box and make the songs use more notes,
by going to edit->add note.

You can change the keys by editing options.txt.

You can change the instruments used for the songs. Just go to
edit->edit instruments.
To change the first instrument used for the melody,
Click the button that says "select melody instrument 1".
To change the second instrument used for the melody,
Click the button that says "select melody instrument 2".
To change the instrument used for the chords,
Click the button that says "select chord instrument".
You can change the instruments by editing options.txt
you can see http://www.midi.org/about-midi/gm/gm1sound.shtml for a list of instrument numbers