I think this is aimed at middle/high school students. It probably can be interesting for adults, but I'd really recommend picking up a book such as Fundamentals of Computer Graphics by Shirley and Marschner [1].
Yeah it seems to be aimed at teens, but this is so far beyond most excellent high school students. They're dropping in terms and concepts which you don't touch on until the final years in an undergrad, with a focus on graphics.
Great lessons.