Would you consider things like this abstract or just doodling or what?
>>2968080
Doodling, it's fun but not anything worth showing.
a huge waste of time
>>2968080
An exercise in textures and materials if done properly.
It depends on where those images are coming from. It is hard to say with no context.
Abstract doodling
pattern making
>>2968080
Pretty cool. It's not something I'd hang on the wall (although it's better than 90% of the stuff hanging in galleries) but it's good practice for rendering patterns, like in cloth, on a dress, or curtains, or something. Plus, doodling like that is really relaxing. And, it's good exercise for pen/pencil control.
If you feel like it, start with a framework of curves like that, and fill in each segment with crosshatching. That would be a great way to practice it.