[omoikane]

See also:

https://winter.dev/articles/gjk-algorithm

This one has an interactive demo near the end that shows Minkowski difference.

[saturnV]

I have made an implementation based on this article before.

https://dyn4j.org/2010/04/gjk-gilbert-johnson-keerthi/

It was years ago but I remember it was the only good ressource I could find that allowed me to understand how it works.