[[File:DrawingHands.jpg|thumb|upright|"[[Drawing Hands|"Drawing Hands"]]", a drawing by [[M. C. Escher]]]]In [[mathematics]] and [[computer science]], '''mutual recursion''' is a form of [[recursion]] where two mathematical or computational objects, such as functions or data types, are defined in terms of each other.<ref>Manuel Rubio-Sánchez, Jaime Urquiza-Fuentes,Cristóbal Pareja-Flores (2002), 'A Gentle Introduction to Mutual Recursion', Proceedings of the 13th annual conference on Innovation and technology in computer science education, June 30–July 2, 2008, Madrid, Spain.</ref> Mutual recursion is very common in [[functional programming]] and in some problem domains, such as [[recursive descent parser]]s, where the data types are naturally mutually recursive, but is uncommon in other domains.
