Artist photographed simple images of impossible figures, which were painted by chalk on concrete walls and roads. Model on each photo accentuates impossibility of figures and foregnness of these painting in such environment. It seems that images of impossible figures were put over photo in digital photo editing program, but it is not.
Artist's site http://hlawka.com.
Images were found at http://www.behance.net/gallery/Impossible-Anamorphose/496090