If you are wondering what to paint, you might make something up, maybe break a few of your rules, if you have any. Let it be very easy. This picture was meant just to have a few irregular shapes and a contrasting background, with a variety of edges separating them. Two people made it at once, which must have broken some kind of rule.
With no photo, no objects, nothing to duplicate, the odds of getting it wrong go way down.
The less you correct, the better (Is that a rule?).