A blurry photo of a spider in front of Stacy's studio (our landlady.) It's odd quality is that it would weave that thicker line diagonally across its web. Stacy said that they usually weave two lines, as an "X", but we mostly just saw one line and often the two ends did not meet in the middle.
Also, the spider's legs were clumped in four pairs (as seen here), and tyically a pair sat right on one of the thick lines.
I suspect it might be a way to attract a mate, because the "X" is shaped like the spider?