I decade ago I had fun creating animated GIF files. For example, I “drew” many compass constructions:

  http://infomotions.com/blog/2010/12/ruler-compass-by-andrew-sutton/

I did something similarly a few years before that:

http://infomotions.com/blog/2008/07/arscience/

In both cases I drew images and then I used a program called GIF Animator, I think. 

Now-a-days I sure the process is similar. 

—
Eric Morgan