Drawing circles point by point from sine and cosine seems pretty first principles to me.

This.

> I do not understand how this is from "first principles"?

What would be "first principles in animation", in your opinion?

What so you want, have them write an OS first? Or should they minw for rare earths to build their own CPU.

This is about how to do animations with primitive shapes, that knowledge would probably translate to many other environments. You could even follow the tutorial with pen and paper if you are into that.