13.1 Rectilinear Grids
 13.2 Dual Graphs
 13.3 Triangular Grids
 13.4 Hexagonal Grids
 13.5 Topological Grids
 13.6 Functionality
 13.7 Scan Converting Lines
 13.8 Scan Converting Circles
 13.9 Scanline Fill Polygons
 13.10 Suggested Problems