1. Ceci n’est pas une pipe, non plus. This is an equation whose solution set is a pipe. So the picture is coded by a description. In this sense, it is like a PS file.
2. Squaring the Circle. A square and a circle with exactly the same number of pixels. The image is very sensitive to scaling and rotation. So it is very different than a PS file. (Actually, this is not the original version. The original one has dimensions 1500×750.)