Changes

[[FILE:EschersAscending_and_Descending.jpg|border|right|thumb|link=http://www.mcescher.com/Gallery/recogn-bmp/LW435.jpg| [[:Category:M. C. Escher|M. C. Escher]], Ascending and Descending, 1960 <ref>[[:Category:M. C. Escher|M. C. Escher]], Ascending and Descending, 1960, [http://www.mcescher.com/Gallery/gallery-recogn.htm Picture gallery "Recognition and Success 1955 - 1972" ] from [http://www.mcescher.com/ The Official M.C. Escher Website]</ref> <ref>[https://en.wikipedia.org/wiki/Penrose_stairs Penrose stairs from Wikipedia]</ref> ]]