- learning project (focus on learning)

- side project (focus on functionality)

- cv-enhancing project (focus on optics, what the original article was mostly about and against)

In my experience, side projects are by far the most fun. All of the learning projects I've done in the past had some goal to achieve, something I could show someone and feel proud. I find it difficult to learn just for the sake of learning. Perhaps this is why I struggled with schooling.