A prayer wheel is a cylindrical wheel (, ) on a spindle made from metal, wood, stone, leather, or coarse cotton, widely used in Tibet and areas where Tibetan culture is predominant. Traditionally, a mantra is written in Ranjana script or Tibetan script, on the outside of the wheel. The mantra Om mani padme hum is most commonly used, but other mantras may be used as well. Also sometimes depicted are dakinis, Protectors and very often the eight auspicious symbols (ashtamangala). At the core of the cylinder is a "life tree" often made of wood or metal with certain mantras written on or wrapped around it. Many thousands (or in the case of larger prayer wheels, millions) of mantras are then wrapped around this life tree. According to the Tibetan Buddhist tradition based on the lineage texts regarding prayer wheels, spinning such a wheel will have much the same meritorious effect as orally reciting the prayers. Nomenclature and etymology Prayer wheel or mani wheel (). The Tibetan term is a contraction: "" itself is a contraction of Sanskrit cintamani; "" is Tibetan for dharma; and "" or "" means chakrano. The common term, “prayer wheel” is a double misnomer. A long strip of rolled-up paper bearing printed or inscribed mantras rather than prayers, per se, is inside the cylinder. The term “mantra mill”, in contrast to “prayer wheel”, is perhaps a better translation of the Tibetan , since a "mill" refers to a turning process that generates a particular output, in this case generating merit. Origins and history The first prayer wheels, which are driven by wind, have been used in Tibet and China since the fourth century. The concept of the prayer wheel is a physical manifestation of the phrase "turning the wheel of Dharma", which describes the way in which the Buddha taught. Historians, such as , have argued that the prayer wheels developed from Chinese revolving bookcases (), popular among Buddhist monasteries. According to the Tibetan tradition, the prayer wheel lineage traces back to the famous Indian master, Nagarjuna. Tibetan texts also say that the practice was taught by the Indian Buddhist masters Tilopa and Naropa as well as the Tibetan masters Marpa and Milarepa. Kawaguchi mentions in his book that the prayer wheel originated in the Mani Lhakhang where Je Tsongkhapa invented it. Prayer wheels originated from ‘The School of Shakyamuni sutra, volume 3 – pagoda