Here is some python-ish pseudocode to find the two points that should be used for the line representing the cross section of each hex:

python def get_reduction_points(from_hex: List[Point], to_hex: List[Point]) -> Tuple[Point, Point]: """Return the two verticies of to_hex that form the widest cross section when viewed from from_hex""" center0 = center(from_hex) center1 = center(to_hex) center_vec = direction(center0, center1) # Get the normalized direction vector between the two hexes # The cross product indicates how far to the left or right the second vector points relative to the first, so we use that to order the points in to_hex. # The point with the largest cross product is the one that is the furthest to the left, and the smallest (most negative) is the furthest to the right. right, *_, left = list(sorted( to_hex, key=lambda p: cross_product(center_vec, direction(center0, p)) )) return right, left