I doodle constantly. Actually for some non-art classes, it's necessary. I'm an extensively visual thinker and there are times when I need to ground my visual working memory in the present in order to focus on what the professor is saying, sometimes to the point, I don't even take a notebook to class, just a sketch book. Other classes I have to take extensive notes.
I can't share yet. Still not enough posts to link a photo.
All your doodles are wonderful, btw!
EDIT: I can now share images! Sadly, most of my art is on my other laptop (bought for gaming and art, more RAM and disk space) that has a busted charging port, so can't share much right now.
But here is the last doodle I did.

I decided to color and discovered that Painter 11 has an animation feature so tested it out with a very simple animation of it. Personally I'll stick to flipbook pro for animation.