Create a short animation loop with that incorporates at least three (but really you should try as many as possible) of the 12 principles of animations.
You can use any digital tool of your choice: Wick, Photoshop, After effects, etc.
Post it as a gif looping infinitely or a video repeated a few times
(you have to add gifs in their original dimension for them to look animated on this site).
Most of these are more complex than what I expect but they are good references for loops beyond the usual walk cycles: