I just thought of an improvement in my previous post. If you use a regular black ball point to make the map, you can then use highlighters for the color coding. Make sure you have at least 4 distinct colors so that you can mark the four parts of the chord. (Just be sure to put the key to the code somewhere on the page). If you want to really go to town, get 7, and you can color code the 9ths, 11ths, and 13ths. Good luck and have fun!