According to the Vedic Astrology, Yantra is a science which can be utilized through the five elements - earth, water, fire, sky and air; by the recitation of mantras to control nature in one's own interest. Deities are worshipped in different forms and each form is linked to a Yantra. The Yantra employs signs and writings to remove a planet's malicious effects and increase its beneficial results. Thus, Vedic Yantras are the graphic representations of Mantras. Yantras can be drawn, engraved or painted on a variety of substances like the eight tantrik surfaces - gold, silver, copper, crystal, birch, bone, hide (which can include any type of paper), and Vishnu stone (Shaligrama). The Yantras should be beheld daily in the morning and one should lit incense stick or lamp before it every morning. Yantras are equipped for different purposes and every purpose has to be acquired through specific type of Yantras.