A planchette is a small, usually heart-shaped flat piece of wood equipped with two wheeled casters and a pencil-holding aperture pointing downwards, used to facilitate automatic writing. It is believed to produce automatic writing when lightly touched by the fingers. The motion of the planchette is due to the ideomotor effect, but paranormal advocates believe the planchette is moved by the presence of spirits or some form of subtle energy. Planchettes took on a variety of forms during the height of their popularity, with American planchettes traditionally being heart- or shield-shaped, while British planchettes took on classical shapes popularized in early illustrations and newspaper depictions, with round, blunt noses and flat backs. The use of a planchette is featured in the 1948 novel No Highway by Nevil Shute and in The Haunting of Hill House, a 1959 novel by Shirley Jackson.