A few years ago, a Dr. R. Andrew Hicks of Drexel University designed a non-reversing mirror that is a single sheet of glass. The reflection is slightly distorted, however.
News coverage: http://techfragments.com/inventions-non-reverse-mirror/ https://www.newscientist.com/gallery/dn16585-amazing-mirrors
Photo from his website: http://www.math.drexel.edu/~ahicks/images/opticks.jpg