12. Voronoi diagrams and Delaunay triangulations

Oops!  I forgot to hit the record button until 55 minutes into the lecture.

(a. Voronoi diagram definitions)
(b. Structural properties of Voronoi diagrams)
(c. Delaunay triangulation definitions)
d. The in-circle primitive
e. Local Delaunay vs. Delaunay (proof next time)
f. Lawson's flip algorithm.