Ranking on offence minus defence buries an exchange rate in the estimator, and it made the winners at a low exponent the hexes with no exchange at all. Ranking now carries by_offence and by_defence and the proposal set is their union. Also factors the arc test out of gather into volley::bears so stands cannot keep a copy that goes stale, gives the demo a heavier loadout and a closer enemy placement, and prints whether the exponent moved the answer.