You can run a virtual X-Server, like Xephyr or Xnest. They are pretty handy and will make it easy to use root painting programs. Fun Fact: The XScreensaver "pr

You can run a virtual X-Server, like Xephyr or Xnest. They are pretty handy and will make it easy to use root painting programs. Fun Fact: The XScreensaver "preview" function works (worked?) as following: Start an instance of Xnest and run the screensaver rendering the root window there.