Recently my daughter, Athena, sent me some more examples from the English, Belgium-based artist Julian Beever. Beever is a master of trompe l'oeil (visual deception in painting). I call what he does "Eye Foolery" and you can go to my previous posts for more information on this subject: Fooling the Eye and More Eye-Foolery.
I'm especially taken by Beever's chalked street paintings that use the technique anamorphosis. (Anamorphic illusions are drawn in a special distortion in order to create an impression of three dimensions when seen from one particular viewpoint.) This is Julian's site; check him out. Lots o'fun!