Hexagon circle) with vertices given by the six intersections of the edges of a triangle and the three lines that are parallel to the edges that pass through its symmedian point. If the successive sides of a cyclic hexagon are "a", "b", "c", "d", "e", "f", then the three main diagonals intersect in a single point if and only if . If, for each side of a cyclic hexagon, the adjacent sides are extended to their intersection, forming a triangle exterior to the given side, then the segments connecting the circumcenters of opposite triangles are concurrent. If a hexagon has vertices
Campaign Hexagon System Campaign Hexagon System Campaign Hexagon System is a supplement for fantasy role-playing games published by Judges Guild in 1977. "Campaign Hexagon System" is a GM's aid: a book of blank hexagon sheets overprinted with larger gray hexes so the GM can integrate wilderness maps of varying scales. It includes tables for generating wilderness terrain. "Campaign Hexagon System" is a booklet of which the main portion is devoted to over 60 blank campaign hex grids. A rectangular hexagonal tessellation of about 1000 small hexes appears on each page, and on this grid is superimposed a large hex representing 5 miles across