L26A
       1. Review: Dupin Indicatrix and Its Graph
       2. Example: Monkey Saddle
 
L26B
       1. Examples: z=y^3 Rotated About z=1 and Cylinder
       2. Derivation: Gauss Curvature of a Surface of Revolution
 
L26C
       1. Derivation: Gauss Curvature of a Surface of Revolution (cont.)