The core functioning of Yantras is known as "shape energy" / "form energy". The main concept behind the functioning is that every shape releases a particular amount of frequency and energy. Some of the examples of energies from shapes are the mandalas in eastern philosophies, the Star of David, the five pointed star (pentagon), Christian cross, pyramids etc. Numerous shapes carry specific 'powers'. Some Yantra carry evil or destructive energies, while some carry constructive energy. However, Yantra Yoga carry only beneficial and harmonious energies.
When an individual concentrates completely on a Yantra, his mind is automatically "tuned in" by RESONANCE turning into a particular form of energy receiving from the Yantra. This method of RESONANCE is preserved and improved over a period. The Yantra acts only as a "tune in" path or a doorway to divinity. Here, it is important to know that the subtle energy is not emitted from the yantra, but from the universe.
Yantras are doorway to create the aura of RESONANCE with the energies of the UNIVERSE. Yantras has the power to connect with elevated energies and entities, and is the priceless path to spirituality.
Yantra is a source that takes us to path into absolute. When our mind is completely focused on a Yantra, the mental stress goes away. Eventually, the object is released when the concentration can remain empty and silent. If the concentration stays intact and with the right use of mantra, there is a high possibility of having a union with God by the geometric conception of a Yantra.
The Yantra is a microcosmic representation of the macrocosm. It is a point or path and an outer / inner doorway. These Yantras are fixed on a particular deity and so by tuning into the diverse Yantras, you can tap into specific divine or a creative force.
Yantras are designed in such a way that you will find eye at the centre, and is symmetrical. Yantra can be designed or produced on paper, wood, metal, or earth, and they can be 3-dimensional.