The set of all lines through a point. The term was first used by Desargues (Cremona 1960, p. x). The six angles of any pencils of four
rays are connected by the relation

and the lengths satisfy

(Lachlan 1893).

Woods (1961) uses the term pencil as a synonym for line segment range, and Altshiller-Court (1979, p. 12) uses the term to mean
sheaf of planes.