Imagine a pond, quiet and tranquil. The surface of the pond is smooth as glass, and reflects the moon on clear nights. Beneath the mirror, however, is stagnation: the slime of beasts and eggs of insects collect in the still water, polluting it with foreign contaminants. Thick muck has collected at bottom, and refuses to let go of what its settled upon. When this placid tableaux is disturbed, then the pond and the image have no recourse: they shudder and reel from the disturbance, distorting the facade and thrashing chaotically until calm is restored.

Imagine a stream, fast and cool. The water churns and writhes upon the rocks, frothing white before flowing on. Errant leaves are swept up in the current, powerless against the forces that drag and pull it along the way. Fast fish dart amongst the stones, going with the flow when it's useful and swimming against when its needs conflict with the current. And yet, the river always flows one way, across the same stones and into the same seas while never straying from its banks. As time goes on, the stream will cut deep, then wide, and become a river, but continue to wash clear.

Imagine a flood, merciless and powerful. Some ancient construct has been destroyed, and now unstoppable forces cut a swath of devastation. The water is brown with mud as it tears across the countryside, caring not if tree, stone, man, beast, or building is swept away. No force can prevent it from doing what it wants to do. But once its energy is spent, it's gone. The devastation and destruction remain, but its causes have since vanished. What was there may never come back, or might grow back next season, but it won't be the same thing that was washed away in the deluge.