Originally Posted by postalelf Understanding Simpsons Beard Theory The Principles: Here we see a highly simplified animation of Groundskeeper Willie's Mouth. Here, the flesh folds from the outside to the inside, like a regular human. Most of the inside of the mouth is dark and cannot be seen, but some of it is exposed to the light, this can be seen on pratically every character on the Simpsons, as they all have an inside lip. Beard theory suggests that the beard attached to the outside area of skin folds itself ...