some pics from the experiment done with the clear pin(set to 0) on the renderer(dx) node. you can get nice effects by simple texture transformation...

{picture file=img/wiki_up//render_0001 copy.jpg}{picture file=img/wiki_up//render_0005 copy.jpg}{picture file=img/wiki_up//render_0011 copy.jpg}{picture file=img/wiki_up//txrot0011 copy.jpg}