"Yantras are mystic diagrams and geometrical designs on which certain lettered or syllabic characters are written. They are made for the most diverse occasions and purposes. They are drawn or engraved on strips of palm-leaf or copper or gold foil and have the significance of amulets. They are worn in a little metal case round the neck or upper arms or even loins, as protection against any possible danger or harm. Some are made to injure another person or to augment the power of a spell against somebody."