Ever heard of anamorphosis? This is the creation of 3-dimensional art on 2-dimensional surfaces, such as sidewalks. This technique is all about perspective. Leonardo Da Vinci was one of the first to combine mathematics with art, creating one of the first known anamorphic drawings.
Anamorphosis works by applying different perspectives into one image. An artist can use math and the basic rules of perspective to make an image appear to fall into or jump out of a 2-dimensional surface. One such rule uses parallel lines drawn in convergence to create depth in a single surface.