You have probably seen Escher's
Print Gallery; the drawing showing a viewer looking at a picture in a gallery, and the picture encompassing the entire scene. Some mathematicians at Universiteit Leiden have
analysed this picture, "straightening" it out using specially written software, making a straight recursive picture (known to the Dutch as a "Droste picture", after recursively-designed cocoa packets in the Netherlands) of the Maltese cityscape in the picture, and using that to make other things, from doubly recursive versions of
Print Gallery to doovy-looking animations which zoom in infinitely (when looped). (via Found)