"Generations of Zen teachers have found Mu to be a particularly useful tool for breaking through the conceptual fog most of us live in. The realization of Mu often sparks an enlightenment experience. Kensho is something like cracking open a door or glimpsing a bit of the moon behind the clouds -- it's a breakthrough, yet there is more to be realized."

"Yantra (यन्त्र) (Sanskrit) (literally "machine, contraption" is a mystical diagram, mainly from the Tantric traditions of the Indian religions. They are used for the worship of deities in temples or at home; as an aid in meditation; used for the benefits given by their supposed occult powers based on Hindu astrology and tantric texts. They are also used for adornment of temple floors, due mainly to their aesthetic and symmetric qualities."

~Wikipedia