I had a small piece sitting around that I'd started using oil pastels on matboard. I also had a box of new acrylic paints including colors I'd never used before. I started playing around with the piece and the paints while waiting for something else to dry. I mindlessly doodled around the center blue/green oval. Viola, mindless worked.
Q. Oil pastels and acrylics on matboard. Maybe 7 x 12