Painting for Worldcon

Unexpectedly I am going to Worldcon, which is a large science fiction convention which this year, happens to be in Chicago. Since I wasn't planning on attending, I will have to paint fast if I want something in the art show. Or I will have to repurpose something that I already have, to make it fit the rules that all displayed art must be of a "fantasy, science fiction, or fannish nature."

One year, right before a convention, I found a landscape in my basement; and I painted a UFO on it in the corner. It was sold, and I think it got a ribbon, too.