These are projects created in Wolfram Mathematica.
Links are given to cloud versions but the animations run better if you download the notebook (.nb) files and use Wolfram Player.
https://www.wolfram.com/player/
https://www.wolframcloud.com/obj/combsbt/Published/pendula.nb
This is a project made to explain the apparent cyclical motion of an array of pendula as seen in the video below. Click on the image below to see a video.
An interesting part of modeling this came in the form of a small angle approximation. Here you can see the difference in complexity of using the full restoring force (dependent on amplitude) vs. the non-amplitude dependent approximation.
The difference in results can be seen in the notebook file linked above.