I have finally found out. The front pattern does move--and no wonder! The woman behind it shakes it! Sometimes I think there are a great many women behind, and sometimes only one, and she crawls around fast, and her crawling shakes it all over. Then in the very bright spots she keeps still, and in the shady spots she just takes hold of the bars and shakes them hard. And she is all the time trying to climb through (Charlotte Perkins Gilman "The Yellow Wallpaper," 30).