Sometimes while researching something or other I end up trying to generate a picture of what's going on. Usually this takes an afternoon or so ... I hack away to get some kind of crude picture, hopefully figure out what I wanted to, and then forget about whatever computer code I wrote.
However, it occured to me that others may want to see the pictures too, perhaps for the mathematical content, or maybe just for fun. So why not put them here? I also explain how I made the pictures, since sometimes it isn't too obvious how to do it. Usually I use existing programs like gp, porta, geomview, ... , all patched together with scripts. Of course the real pros use C/C++ and graphics libraries like mesa and glut, or even write their own graphics libraries, but that's too hard for me.