Chalk Shadow Art: These were created by artist M Neff, who goes around outlining shadows in chalk. A beautiful combination of chalk and shadow makes it really attractive. During the day, however the combination can be seen only for a while as the shadow moves on which can be seen in this video. But during the night, with the light, the beauty of it can be seen once again.
Henrietta Swift's Shadow Art: These come from the collection of work of Henrietta Swift, a project with C Smith intending to recreate famous structures. Impressive.
Shadow Illusions: Not everything you see is true; a series of shadow illusions shows that sometimes what the eye perceives is not the entire truth.
Roof Art Barns.
3D Street Paintings.
Optical Illusion With Trucks.