By implicit invitation :-) : Without carefully thinking about the fine points, SolarWind comes close enough to Calvin for a working model, no? I'd do a rough approximation to Hobbes (the striped version) but not enough for it to be a good model. Russell --=20 http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist .