This is what's with this background!
That background and this one are taken from elements of a series of Frank Lloyd Wright's art-glass (or stained glass) pieces that he did for the Avery Coonley Playhouse. In fact, I got the image for the main page background from the site that that link is to - a very good site, by the way! One of these pieces is to the right.

Author: Dafydd Cyhoeddwr.
Last Updated: Friday, April 10, 1998
Version 2.5