I really have discovered something at last.
Through watching so much at night, when it changes so, I have finally found out.
The front pattern does move—and no wonder! The woman behind 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 very shady spots she just takes hold of the bars and shakes them hard.
And she is all the time trying to climb through. But nobody could climb through that pattern—it strangles so; I think that is why it has so many heads.