It seems to me a profound thing... that I can seem to type most any character I've come across. To follow their progression in Model-A -- moreover, to follow different progressions in characters created by the same people -- seems to me a very mysterious phenomenon. Even more profound is the question of how you guys (the more artistically talented of you) capture the phenotype of a particular type in the physical representations of your characters.
I know there must be a perfectly understandable method to this, but I need for you to explain it to me! (if that's not too much trouble )