power diagram

 page 12 from Yantra

Yantras function as revelatory symbols of cosmic truths as instructional charts of the spiritual aspect of human experience. 

All primal shapes of a yantra as psychological symbols corresponding to inner states of human consciousness, through which control and expansion of psychic forces are possible.

It is for this reason that a yantra is said to embody a 'functiona-principle' (Kriya-rupa).

By constant reinforcement in ritual worship the apparently inert yantra forms shake off their dormancy and act together as emblems of psychic power.

In this case, the yantra is said to move beyond 'form' and 'function' and emerges as a 'power diagram'  endowed with a self-generating propensity to transform a mundane experience into a psychic one.

It is at this point that the yantra is said to be 'revealed'. 

Although its outward meaning may be relatively easy to undestand, the inner meaning that gives it its efficacy is difficult to grasp because its archetypal forms as basically concerned with the inner facts of psychic experience, gained through intuitive vision.

A yantra is a substitute for an anthropomorphic image of the deity.... a deity's yantra may bear no resemblance to the iconographic image, whose proportions and human attributes are fixed by the traditional canon.  The yantra is its 'trans-form' its abstract translation. A yantras retains the suprasensible vitality of an image, expressing the sense and spirt of the original.

As the body is to the soul and oil is to the lamp, a yantra is to the deity.
Kularnava Tantra

       

Yantra: The Tantric Symbol of Cosmic Unity by Madhu Khanna and Ajit Mookerjee