Uncle Norm is going to a masquerade ball and he needs a mask. Problem is, he doesn’t know where to start. Kevin and Alanna turn to a photographer for help. He teaches them about bilateral symmetry. By taking cool photographs of Alanna’s face, we see that both sides of the face are not created equal.

The Gist: This episode is about bilateral symmetry and geometric mirror images, and introduces the bilateral category of animals (including humans) that are more or less left/right symmetric and the vertical mirror line (or sagittal plane), which divides the body into two halves of equal proportions.