Here is an idea inspired by my entry in today's PSC contest.
Using only the paints available in the displayed paint cans,your ingenuity, the brushes, custom or otherwise- in Photoshop, and/or the Photoshop custom shape tool, paint an image onto the blank canvas. The only criteria related to creating the image is the criteria that applies to all images submitted to the PSC site. The above rules can be bent in one way: 1. If you want to use a color that is not supplied in the paint cans, then change the color of the paint in the can. You can also put the colors in the paint cans in the foreground and background squares and apply the colors using whatever size brush etc works for you.
Also the image may be totally from "scratch" as long as it is painted, and only the colors in the paint cans are used.
An added feature is that "spin-offs" are permitted. For example, someone may start a painting and leave it for someone else to finish. The basic criteria related to using the supplied paint and brush tools are still in effect, and you must identify your spin-off and
how you want it to work within the framework of the established criteria..
Photoshop textures, filters, lighting, adjustments etc. can be applied to the painted image.
Here is the canvas.