(Slide 9)

Other common examples of cell complex are the triangulation, which is a simplicial 2-complex, the tetrahedralization (a simplicial 3-complex), a regular grid (cube complex), and so forth. All of the mathematical and computational structure we are going to develop will apply to all of these. In these illustrations, the 2-cells are colored blue, the 1-cells green, and the 0-cells are not colored separately, but occur at the intersection of two or more 1-cells.