Watermelon

I was looking up some evening classes to see if there was any of interest to enliven my twilight hours.
Scanning quickly through the class titles I came across "Learning to paint watermelons."
I saw a classroom of students poised with a watermelon and a paint brush in front of them.
Do you paint a watermelon like doing boiled eggs at Easter?
Perhaps one needs to start by painting it with a plain undercoat. Although maybe that is the challenge of painting watermelons - creating a design that uses that natural pattern in the skin.
Maybe it is not a class painting on watermelons, rather one learns to paint a picture of a watermelon. A naked watermelon sits at the front of the room with students trying to capture its essence on paper.
Rereading the details, it turned out my brain had been a bit too fast on word completion. The course title was "Learning to paint watercolours."
I wonder if they have considered a watermelon painting course? It might have potential.