A method of aiming or aligning in which two overlapping fields of view fixed with respect to each other are produced, one of which is inverted and reversed with respect to the other and superimposed thereon. Given a target in the overlapping fields of view, movement of the fields of view to cause a given...http://www.google.com/patents/US4367949?utm_source=gb-gplus-sharePatent US4367949 - Aiming method and means
