I'll take any opportunity to spread the word about Freya Holmér's incredible overview of splines, "The Continuity of Splines": https://www.youtube.com/watch?v=jvPPXbo87ds

It's one of the single most informative and useful math videos I've ever seen, and taught me so much stuff I had no idea existed. I've been using beziers since I was a teen learning a pirated version of adobe illustrator 6 or 7 and I had simply assumed beziers were all you needed. NOPE!!!!

Not only that, it allowed me to realize what was wrong with a game prototype I was working on at the time, which had exactly to do with the continuity problems discussed in the video. Cannot recommend it enough.