For some of my artwork, I use a program I created to make a basic shape. It basically plots electric potential on a plane. You give it either a) a list of points/charges; b) a short script to create a spiral type design (the only thing I have implemented); or c) mouse clicks (left/right = positive/negative). It will render a graph of the resulting potential that can be easily used in, for example, photoshop. If anyone is interested in trying it out, just tell me, and I can give you the executable (jar) file, the java source, and some example script/input files. For some examples of this program's output, check out any of my deviations named 'EP' (for the photoshopped versions), or my scraps named 'EP' (for the original output).