What is the author's likely purpose for the narrator's lengthy and changing descriptions of the wallpaper?

In the story, wallpaper, a usually feminine, floral decoration on the interior of walls, is a symbol of female imprisonment within the domestic sphere. Over the course of the story, the wallpaper becomes a text of sorts through which the narrator exercises her literary imagination and identifies with a feminist double figure.

When John curbs her creativity and writing, the narrator takes it upon herself to make some sense of the wallpaper. She reverses her initial feeling of being watched by the wallpaper and starts actively studying and decoding its meaning. She untangles its chaotic pattern and locates the figure of a woman struggling to break free from the bars in the pattern. Over time, as her insanity deepens, she identifies completely with this woman and believes that she, too, is trapped within the wallpaper. When she tears down the wallpaper over her last couple of nights, she believes that she has finally broken out of the wallpaper within which John has imprisoned her. By tearing it down, the narrator emerges from the wallpaper and asserts her own identity, albeit a somewhat confused, insane one. Though she must crawl around the room, as the woman in the wallpaper crawls around, this "creeping" is the first stage in a feminist uprising.