Animating Shapes

Here's a piece of really fun animation from one of the new Mickey Mouse shorts. If you haven't seen them, you are totally missing out.

I always wonder how such quick and snappy animation can feel so smooth and fluid. One reason is because the animator is "animating shapes." To define animating shapes, I quote Eric Goldberg: "Successful and fluid animation of shapes relies on the tricks hand-drawn animation can exploit in order to keep masses consistent, regardless of reality!  In other words, just because something would occur in real-life one way doesn't mean that animators don't have the means to distort that physicality to get a smoother effect on screen" (Goldberg, Character Animation Crash Course, 165).