Took a Shading Course

This course was only 1.5 hours long and what was taught wasn't completely new to me, so I completed it quickly.
I liked that it articulated lighting concepts that I was vaguely grasping at via intuition before. Now I can be more intentional about how I shade.
https://www.udemy.com/course/the-art-science-of-drawing-shading-fundamentals