I guess the "Good and Evil" drawing can be viewed as a symbolic representation of the duality of man, showing the different sides in both color and composition.  The fact that the facial expression are identical bring the two sides together. 

I remember when I drew this, I had a lot going on in my head.  I was in a positive place, but I kept getting hit with a negative energy from folks around me in the office at the time.  Feeling like I was being pulled in different directions, the best thing I felt at the time for me to do was to put those feelings down with the pencil (or stylus at this time, as I drew it digitally).