I have a Buddha Board, which is a tablet that you paint on with water, using a bamboo brush. The water turns black and begins to fade in a few seconds. It was designed as a meditation tool, but I'm using it to be able to be spontaneous in a very easy medium. I photograph what happens and then put it into Photoshop and fool around until I get results I like. Most often, the end result is nothing like what I start out with. Since the colors are created on the computer, they look best on a screen, so I have a screen in my living room that shows the pix in a slide show. I've also done some printouts that are a lot better than I expected they would be. Water is my favorite element, and computers are fun, so this is very liberating for me. Obviously, there are limitations to working this way, but that's true of any medium.