512px|thumb|looping animated cutaway view of boy's surface. bernard morin is a french mathematician, specifically a topologist, born in 1931, who is now retired. he has been blind since age 6 due to glaucoma, but his blindness did not prevent him from having a successful career in mathematics. morin was a member of the group that first exhibited an eversion of the sphere, i.e. a homotopy (topological metamorphosis) which starts with a sphere and ends with the same sphere but turned inside-out. (see smale's paradox.) he also discovered the morin surface, which is a half-way model for the sphere eversion, and used it to prove a lower bound on the number of steps needed to turn a sphere inside out. he discovered the first parametrization of boy's surface (earlier used as a half-way model) in 1978. his graduate student franÃ§ois apÃ©ry later discovered (in 1986) another parametrization of boy's surface, which conforms to the general method for parametrizing non-orientable surfaces.weisstein, eric w. "boy surface." from mathworld--a wolfram web resource. http://mathworld.wolfram.com/boysurface.html morin worked at the institute for advanced study in princeton. most of his career, though, he spent at the university of strasbourg. image:morinsurfacecrossview.png ::::morin's surface. ==references==  * george k. francis & bernard morin (1980) "arnold shapiroâs eversion of the sphere", mathematical intelligencer 2(4):200&ndash;3. ==external links== *photos of morin with stereolithography models of sphere eversion. *the world of blind mathematicians, pdf file at the american mathematical society's website.  
1931_births Blind_people_from_France French_mathematicians Living_people