How to create endless 2d curvy terrain?


I have watched this video on how to create 2d terrain but didnt understand most of it:

I was wondering if anyone could help explain it and possible give some code to help me create a similar effect?

Any help is greatly appreciated, thanks.

I haven’t done this in theory, but here’s an idea:

As your player moves, create clones of the 2D terrain in front of his path so he can walk infinitely. This will cause a drag on the memory so destroy the terrain clones behind him. While hard to explain in text, it would be pretty easy to code and would work flawlessly.