From Taoism by John Blofeld
''Since pure yang, also known as cosmic yang, pertains to heaven and pure or cosmic yin to earth, there has to be a means for them to comingle. It is taught that, at certain places, there are 'dragon veins', that is to say invisible lines running down from the sky into the mountains and along the earth, whose function is rather similar to that of the psychic channels within the human body which play such an important part in acupuncture and in yoga...
Into these dragon veins pours down the yang ch'i (cosmic vitality) to mingle with the yin ch'i (vitality of earth). Invisible to the ordinary eye, these veins can be detected by those learned in the science of yin and yang.
This concept is clearly reflected in Chinese landscape painting, in which the veins are delineated as great sweeping curves marked at their source by the contours of clouds, then by the undulations of mountains and hills, and finally by the meanderings of rivers or some other landscape features.
There are other ways in which paintings convey Taoist concepts more directly than verbal description, especially that the entire cosmos is formed of spirit. The voidness of the non-void is hinted at by vast expanses of ocean, snow, cloud and mist, and by solid objects which seem just on the point of emerging from or melting into the void.
Man's triviality in relation to heaven's vastness is suggested by rolling landscapes in which mortals and their dwellings appear insignificant against the grandeur of their surroundings. Mountains appear cloudlike; clouds resemble mountains; rocks and tree trunks appear strangely animated; the contours of men and animals are so united with those of natural objects that they appear to be of a single substance.
Apparently trivial objects - say, a dragon-fly perched on a twig - arouse a sudden intuition that each tiny creature is a particularisation of avast and holy universality, an embodiment of the inconceivable immensity of the Tao.
From all this one is led to understand that the cosmic vitality sweeping down through the dragon veins spreads out and infuses the entire creation.''