They are generally drawn on gold, silver or copper sheets. Colours are avoided. As in Padmas straight lines, circles, triangles and rectangles are drawn but on metallic sheets. A perfect yanthra includes ten organs namely.
1.Jeevan            6. Yanthra gayathri
2. Pranan           7. Manthra gayathri
3. Sakthi             8. Prana Prathishta
4. Nethram         9. Bhootha beejam
5. Shrothram       10. Dikpala beejam
An yanthra can not attain its intended divine power merely through correct geometric inscription. It should be made divine in different stages. ‘Punyaha sudhi’ is the first process. ‘Saparivara pooja’ is the second phase for that ‘Prana prathishta manthram’ and charectric manthra of that particular yanthra must be chanted touching the yanthra. Yanthra can be worn only after finishing these process of preparation. Protection (raksha) , realisation of aim (karyasadhyam), destruction (nigraham) , recovery from illness (rogashamanam), stoppage of certain activity, (sthambhanam) Acquirement of something (aakarshanam) , get avoiding something (vidveshanam), driving away of evil forces (uchadanam), get the admiration, attraction, respect, approval etc. of some person (vashyam) are the objectives of yanthra wearing. Nigraham, Sthambhanam and Vidveshanam are ofcourse negative ends and so noble thantrik practitioner do not prepare yanthras of such nature.
1. Vaishnava Yantras
2. Shaiva Yantras
3. Shaktheya Yantras (Devi)
4. Other Yantras