Finally they waddle down a drift into a vault, half the dimensions of the main vault, that is illuminated from above by dim bluish sky-light. Goto Dengo turns on some electric lights as well. "The fool’s vault," he announces. He points up the vertical shaft in the ceiling. "Our ventilation has been courtesy of this." The General peers upwards and sees, a hundred meters above them, a circle of radiant green-blue jungle quartered by the spinning swastika of a big electric fan. "Of course, we would not want thieves to find the fool’s chamber too easily or it wouldn’t fool anyone. So we have added some features, up there, to make it interesting."