YANTRA

Yantra is the Sanskrit word for "instrument" or "machine."  Traditionally such symbols are used in Eastern mysticism to balance the mind or focus it on spiritual concepts.

The act of wearing, depicting, enacting and/or concentrating on a yantra is held to have spiritual or astrological or magical benefits in the Tantric traditions of the Indian religions.

Many yantras seem like nothing more than an interwoven complex of geometrical designs centered upon a point (bindu).  A yantra, though, is a complex of stored imagery of sight and sound--yantras often have an accompanying mantra--and psychic and mystical content. 

Though two-dimensional, yantras are conceived as having depth and full dimension.  They may be drawn or painted on any material, out of any substance.  A yantra is often enclosed by a square, signifying the cosmic dynamics and the four corners of the universe.  Yantras are thus worshiped as containing divine presence.

The yantra is sometimes confused with a mandala, the former appropriate to a specific devata (god, or guardian spirit), the latter implying any devata.