If you've ever taken an entry level drawing course, you know that perspective is both important and kind of hard to master in the beginning, especially when you're working on a flat surface. Imagine trying to do the same thing, but on an object with many flat surfaces. According to his website, Patrick Hughes invented "reverse perspective" in the mid 1960s, a style that uses 3D surfaces and a mastery of perspective to create an image that looks like a flat painting when you stand directly in front of it, but moves as you move around it.
One of the artists that Hughes calls an "imitator" is British artist Brian Weaver. The video below of a painting by Weaver depicts an art gallery with famous works on the walls, including Roy Lichtenstein's Portrait (1977) and Keith Haring's Pop Shop VI (4) (1989). This kind of painting really should be seen in person, but it is still pretty cool to watch it morph as the camera moves.