Yantra is a mystical diagram that possesses control over cosmic forces. It can be called as the divine storehouse of energy, which picks up cosmic rays emitted by the planets and transforms them into constructive vibrations. These energy impressions are then transmitted to the surroundings where Yantra is placed, thus destroying all the destructive forces within the vicinity. Vedic Yantras are geometrical figures intended to represent the basic energies. Right from a simple dot (bindu) to complex geometrical figure, each is symbolic of some form of energy.

Yantra is derived from the word Yama. It destroys all the malefic effects of planets, regulates the energy and converts them in a positive power. It is an interlocking matrix of geometric figures, circles, triangles and floral patterns that form fractal patterns of elegance and beauty. The person under the influence of Yantra, slowly and steadily benefits by being at the receiving end of all the affirmative vibes of this cosmic conductor of infinite energy.

Features of Yantras
Yantras can be drawn, engraved or painted on a variety of substances. The classical eight tantric surfaces are gold, silver, copper, crystal, birch, bone, hide (which can include any type of paper) and Vishnu stone (Shalagrama). There are two types of Yantras: Bhu and Meru. Bhu yantras are two-dimensional depiction of figures, whereas the Meru yantras are three-dimensional carvings of geometry. There is a specific designated place where a particular Yantra is seated for its full effect. Before establishing a Yantra, it is necessary to energize them by doing `Pranaprathishtha`.

Types of Yantras in Hindu philosophy
Different Yantras are created to give different types of cosmic boons to individual problem. It can range from increasing the sexual powers, to gain harmony in business and wealth or to gain sidhi through meditation. Yantras help the individual with whatever ambition has to be accomplished. Basic elements considered in Hindu philosophy are Earth, Fire, Water, Air and Ether (Aakash). Depictions of all these forces are imbibed in the sophisticated and unbelievingly accurate mathematical construction of Yantras. Although these talismans were invented thousands of years ago, the highly developed mathematical and architectural concepts are still an object of awe and wonder for most researchers. For earth element rectangular Yantras are made, whereas for water element, circular shapes are assigned to get merits of that particular form of energy. Triangles are used for fire element. Complex shapes take in all these forces to generate an explicit force. Different elements have different objectives. Earth element passes on ambition, stability, comforts and material success. Water element imparts depth, wisdom, affection, love and emotional stability. Air element imparts intelligence, power of speech and removes hurdles. Fire element helps in gaining success, respect and in averting troubles. Aakash / Ether element helps in spiritual enlightenment, overall success and knowledge.

Types of Yantra in Mohammedan Practice
In Mohammedan practice, Yantras have been divided into four types. They are known as Atshi, Badi, Abbi and Khaki, which correspond, to Fire, Air, Water and Earth respectively. They also have different objectives.

Atshi (Fire) Yantras
They are written on paper, Bhoj Patra, old clothes, Chinawares etc. These Yantras are put in Fire or buried near hearth place or fireplace. They bless the native with success and helps in overcoming the difficulties of life. They also help in controlling dreams (sub conscience).

Badi (Air) Yantras
They are those Yantras, which are hung with a tree or are placed at a height where they should remain in motion. These are used for affection, love affairs or for stopping the vicious speech of another man.

Abbi (Water) Yantras
They are thrown in river, canal, well or any place where there is water as per specific directions. These Yantras are generally used for release of prisoners.

Khaki (Earth) Prithvi Yantras
They are buried under the Chowkhat, cremation path and mountain or at the places where four roads meet. These are used for the death of enemies.

Types of Yantra for Different Purpose
Different types of Yantras have different configuration for various purposes.

Sharir Yantras
They are the ones acting on the Kundalini force in the body. Wearing these Yantra on the body or keeping it in vicinity energises a particular Chakra in the body.

Asana Yantras
They are the ones that give fast effects by placing them below the asana during meditation to achieve higher level of concentration.

Puja Yantras
Through these, worshipping or puja of a particular deity is performed. All these Yantras should be kept in the place of worship, and lighting of incense or Diya is usually mandatory.

Shree Yantra
Shree Yantra is a scientific, cosmic and planetary energy zone. This Yantra is said to bring material prosperity and spiritual elevation. There is a great importance of Shree Yantra in `Vastu Shastra`. Any house with an energized Shree Yantra will be devoid of negative energy and will embody positive vibes within itself.

Navgrah Yantra
This instrument is used for pacifying and enhancing the positive vibes of all the nine planets. It endows the owner with mental harmony, good health, intelligence and overall success in life.

Kuber Yantra
Kuber Yantra is particularly effective in financial gains and prosperity.

Mangal Yantra
Mangal Yantra brings all round improvement in business and health. Mangal Yantra also benefits people with `manglik dosha` and the ones not getting married. It also helps in progeny and paying off the debts etc. A regular worship on Tuesday with 21 day fast is must for its effect.

Akarshan Yantra
This Yantra endows an attractive aura to the person, and makes him / her appealing to all people in general.

Vashikaran Yantra
The Yantra to attract one particular person is known as Vashikaran Yantra.

Saraswati Yantra
Saraswati Yantra bestows knowledge, intelligence and creativity to the possessor.

These are the few examples of popular Yantras. Apart from these, Yantra for each planet (like Surya Yantra, Rahu Yantra) is available to enhance the strong cosmic energy of that planet. Yantra is nothing but an effective stepping-stone for a human quest to materialize the great knowledge regarding our understanding of the universe.