Various types of magic can also be categorized by the techniques involved in their operation. For example, there are contagious magic and sympathetic magic, one or both of which may be employed in any magical work. Contagious magic involves the use of physical ingredients which were once in contact with the person or thing the practitioner intends to influence. Sympathetic magic involves the use of images or physical objects which in some way resemble the person or thing one hopes to influence; voodoo dolls are an example.
Other common categories given to magic include High and Low Magic. Manifest and Subtle magic typically refers to magic of legend rather than what many individuals who practice the occult claim to use as magic, where Manifest magic is magic that immediately appears with a result, and Subtle magic being magic that gradually and intangibly alters the world.