I'm playing with the Example Theme css file.

Added to body
background-image: url(scrapbookPage.jpg); / pattern of page /
background-repeat: repeat-y;
which added the pattern to most of the page. Where it's missing is a "pane" that runs downward from "Admin Toolbox" (if you think of a page in 3 vertical frames, it is as if the right pane has no image background). The background image appears right through #main which has no colour defined, ALMOST to the very edge border, set to be 2px.