Allowed options:
max => maximal face color (default: red)
min => minimal face color (default: yellow)

The methods described below can be used to add more details to drawings created by the following visualization methods:

Polytope::VISUAL_FACE_LATTICE | Polytope::VISUAL_DUAL_FACE_LATTICE

MIN_MAX_FACE (options)
Illustrate the behavior of a linear objective function on the polytope. Draw the filters of the MAXIMAL_FACE and MINIMAL_FACE in distinct colors.

Each auxiliary method always returns the visual object it was called with ($this), which makes it easy to build longer method chains of the kind: VISUAL->DIRECTED_GRAPH->VERTEX_COLORS .