Felice Varini is a Swiss artist known for his uncanny skill with perspective and geometry. His well-known geometrically-inspired optical illusion street art can be found outdoors. The designs seem to float as a whole when viewed from some angles. In others, the viewer sees broken fragments. His optical illusion street art does require a viewer to actively seek the right vantage point in order to appreciate the whole picture.
Implications - My favorite of these Felice Varini optical illusions has got to be the one that seemingly displays a red square with four transparent circles down a hallway. How Felice managed to paint an entire parking lot in this manner, I'll never know.