You should check out the rest of the Licia He's work too. She's doing really cool stuff with watercolors and plotters, with a free course on it actively in the works. Unfortunately her site went down some time recently, yet archive.org has it here:
Interesting approach with the brush. I added a peristaltic pump on mine to pump paint or any fluid to a syringe tip on the XY stage [1]. Example with bleach pointillism to do stuff on fabric [2]
