10.5 x 5.5 inches.
I think there's a broad spectrum--if you're a highly realistic painter, just about anything else is going to seem abstract, for example. Ultimately, though, I think if you're the volunteer Group Admin, you can run your group however you please, and what the Group Admin decides counts as abstract is the definition.
Anyhow, this is a pseudo-abstract--riffing off the clematis growing in my garden.
300 lb Fabriano hot press
Daniel smith quin gold, phthalo blue rs, carbazole violet, a little cobalt blue, and a touch of crayon.