This does not have a very specific meaning, it just expresses an artistic conception. The elegance of the white clouds and the clearness of the spring water. Zen is Buddhism, and the Taoist heart is Taoism. Through the elegance of the white clouds and the clearness of the spring water, you can understand these Buddhism and Taoism. In fact, it is the inner state of mind. Use a calm heart to understand it. These are profound and unfathomable truths.