The three-color conjecture for weak conflict-free vertex-to-vertex guarding

A simple polygon is a polygonal region whose boundary is a simple polygonal curve. In weak conflict-free vertex-to-vertex chromatic guarding, guards are placed at polygon vertices and a vertex is guarded when it sees a guard of a color that no other visible guard has.

Three-color guarding conjecture. Every simple polygon admits a weak conflict-free vertex-to-vertex chromatic guarding with at most $3$ colors.

This conjecture concerns the number of colors needed for weak conflict-free visibility guarding. The source presents it as a suggestion from investigation rather than as a proved result; its resolution is left open.