Impossible Exploration

Objective: Explore impossible objects in Escher's work.

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?

Handin: A sheet with answers to all questions.