In the "The Yellow Wallpaper," how do the changes in the wallpaper in the daylight versus the moonlight affect the mood of the story?

Charlotte Gilman Perkins's "The Yellow Wallpaper" is a
story in which the wallpaper has become symbolic of the cult of the Victorian
Womanhood.  The wallpaper of a "repellent" yellow--which represents decadence--appears
different in the daytime from at night to the unnamed narrator.  She remarks, "This
paper looks to me as if it knew what a vicious influence it
had!"

Perkins's narrator observes that there is a kind of
sub-pattern in a different shade that can only be seen in certain
lights:

But
in the places where it isn't faded and where the sun is just so--I can see a strange,
provoking, formless sort of figure, that seems to skulk about behind that silly and
conspicuous front design....On a pattern like this, by daylight, there is a lack of
sequence, a defiance of law, that is a constant irritant to a normal mind....the pattern
is torturing....

The narrator
remarks, also, that the pattern changes as the light changes.  At night with the
moonlight, the pattern becomes "bars" and the woman behind it is as plain as can be.  By
daylight she is "subdued."  The narrator feels that the daylight subdues the woman.  It
seems apparent that the changes in the yellow wallpaper reflect what transpires with the
narrator herself.  Thus, there is a disturbing mood, a tone of foreboding rebellion, as
she becomes obsessed with the wallpaper, finally feeling that she must free the woman
behind it.