chalk optical illusion
it all depends on how you look at it and what because if you look at it a different way it might look like it is something else. they call it perspectival anamorphosis and it is also called a optical illusions and i think it is cool that they can make that and it all depends on how you make it. Your brain thinks looks at it in a 2D way and it turns it in to a 3D way so when you look at the chalk it will turn in to a 3D way
"Sidewalk Chalk Drawings: 3D Pavement Art and Anamorphic Street Painting." Sidewalk Chalk Drawings: 3D Pavement Art and Anamorphic Street Painting. N.p., n.d. Web. 16 Mar. 2015.