Creates symmetric center-originating slice rays, polygon rings, outward partial polygon paths, and optional supplemental rays. Supplemental rays are mirrored automatically so you can add divisions without changing the base equal-area slice count.
Every polygon-ring edge is a straight line segment. The generator adds only one top-center and one bottom-center polygon vertex so those sides form angled facets instead of a single flat chord.
A top/bottom mirrored pair adds four lines: two aimed at the top edge and their mirror images on the bottom edge. The spread is measured from the center of that edge toward the corners. When polygon rings exist, each supplemental line begins exactly where it intersects the innermost polygon ring and continues to the rectangle edge.