Clouds are magic in the sky. On a perfectly clear day, clouds may suddenly appear from nowhere, literally out of the blue, and soon cover the whole sky with inconceivable rapidity. And they can be gone just as quickly, as you will know if you have ever encountered a sudden rainstorm, sometimes even with lightning and thunder, while hiking in the mountains. When you are scurrying to find a hiding place, the rain suddenly stops, clouds disappear, and the sun shines brightly over the freshly washed cypress trees. Such was my experience when I was a juvenile in Taiwan, a subtropical volcanic island in the Western Pacific where mountains, sunshine, and water vapor are all abundant. The stir-fry of these ingredients is surely an excellent recipe for cloud making.

Ever since I was a child, I have been intrigued by clouds and had wondered where clouds lived and how they can appear mysteriously in the sky and climb up mountain slopes, and how such seemingly solid blocks can stay afloat in air. Nobody seemed to know the answers. Some adults cited an old saying from ancient Chinese literature: “clouds come out from mountains,” but I had never been able to find any “central storage house” of clouds in any mountain in Taiwan.