It includes materials that strenghten the mood.
The iceberg unites the visible and the invisible. Its identity is not limited to its appearance, nor its value to its visibility. We know how voluminous its underwater part is. Yet it always ends up turning over. What was visible disappears. And what remained hidden shows itself. Each iceberg plays a game of fleeting appearances. Its vital centre depends on the rotating movements that bring the submerged volumes to the surface and engulf the others, so that the visible and invisible sides are never the same. To see an iceberg is thus to see the visible and the invisible in alternation. Nothing is immobile, even if everything seems frozen to the eye that remains on the surface.
(Thinking Like an Iceberg, p. 158)