Currently, when you press tab, you can have either a square or circular brush. I was thinking that if different shapes were added it would open up a new range of saves. For example: Strange shaped bombs, Artistic simulations, and I'm sure there's more. An example of different shapes may be: Stars, Hexagons Rectangles etc....
I'm not sure if it's hard to code but I know it will be easier than making shapes by hand.