So for a while I thought I needed a tablet for art like this, but boredom + time makes you creative in ways you wouldn't expect.
I sketched this on a piece of paper and took a picture of it, half in shadow. Shadows are typically blue, and sunlight is yellow. That's an oversimplification, but basically it means that I knew I already had the right colors, I just had to turn the saturation up a few hundred notches. A combination of Google images' basic editing and a free app called Glitch Lab allowed me to layer on some glitchy effects.
Now if only I'd remembered that the Ukrainian flag has the yellow on the bottom and the blue on top ...