- Try this Animated Necker cube applet by Mark Newbold.
- What’s wrong with Waterfall (Magic of M.C. Escher #195)?
- What’s wrong with Ascending and Descending (Magic of M.C. Escher #242)?
- Belvedere (Magic of M.C. Escher #235) contains many impossibilities. Describe as many as you can.
- What's going on in Convex and Concave (Magic of M.C. Escher #201)? What depth cues are ambiguous here? The picture has two parts which are perfectly fine by themselves, but which disagree when combined. Where are the two parts?
- Explore the Impossible Worlds website to see many more impossible figures by other artists, especially work by Oskar Reutersvärd.