We speak of spring and summer, we speak of autumn and winter. These four seasons revolve without ceasing. We speak of north and south, we speak of east and west. These four points respond to the requirements of the centre. We speak of water, fire, wood, metal, and earth. These five elements have their origin in number. We speak of charity of heart and of duty towards one's neighbour, of propriety, of wisdom, and of truth. These five virtues admit of no compromise.