rbc, thanks, but that script works with Tk... which isn't really applicable in the context of CGI, as far as I know... gnuplot looks like it might do the trick, but I'll have to play around with it a bit more. And as to your suggestion, Merlin42, very interesting but a bit beyond me, for now (still interested though). I figure I might as well explain the point of all this anyways: I'm going to be having as data a large number of RGB values, and am trying to plot them all in a 3d cubic space, so one can visually see clustering of the colors. For now I'll try gnuplot some more, but any other suggestions would be great. Thanks.