Agreed. Having worked through Euclid with letters (in class, often out loud, mind you, so that may skew my imagination here) I really cannot imagine that colors

Agreed. Having worked through Euclid with letters (in class, often out loud, mind you, so that may skew my imagination here) I really cannot imagine that colors enhance the process at all. I wouldn't be against colors in addition to letters, but colors alone, despite the superficial aesthetic appeal, seems nutty.