Check out this really nicely made video showing step-by-step how to make a cat and mouse automaton. The narration is in German, but the video is so clear it hardly seems to matter. (Incidentally, if you turn on the YouTube CC function, English subtitles are shown.) This charming automaton was created by Christopher Blasius.
You can download free plans for the cat and mouse automaton from his web site.[ Thanks Charles! ]