Closing plastic disposable cup lid. When I found this posted, I saw someone pointing out that you can accomplish the same thing by stacking cups.
<video controls autoplay loop>
<source src="https://s3-us-west-1.amazonaws.com/hmt-forum/closing_cup_cap.mp4" type="video/mp4">
Your browser does not support the video tag.
</video>
Previously:
https://www.homemadetools.net/forum/...502#post122792
