Began to see—now that we had won—parts of Prof’s plan that had never been clear to me. Inviting attack against catapult had spared warrens—hoped it had; that was plan—but Prof had always been cheerfully indifferent to damage to catapult. Sure, had a second one—but far away and difficult to reach. Would take years to put a tube system to new catapult, high mountains all way. Probably cheaper to repair old one. If possible.