From Neal Stephenson's Cryptonomicon:The background of his [X] screen happens to be a uniform indigo at the moment, but it could be an image. Theoretically you could use a movie ... You can, in fact, take any piece of software and make it into your screen background ...How would you set a program as the desktop wallpaper?
Setting a program as the wallpaper
xorg;desktop;wallpaper
You just run a program on the root window. Most screensavers allow you do do that, e.g.:/usr/lib64/misc/xscreensaver/sundancer2 --rootHowever, most modern Linux environments run a desktop program that covers the whole screen and covers the root window. So you won't see it unless you kill the desktop program.