A portable foldable overhead projector includes a housing having a front opening communicating with an interior cavity, and a bottom aperture communicating with the cavity and closable by a pair of pivoting doors which, when open, support the housing on support legs and accommodate movement of a mirror...http://www.google.ca/patents/US4969733?utm_source=gb-gplus-sharePatent US4969733 - Foldable portable overhead projector
