Symbolism, Imagery, Allegory
The schoolhouse is a confusing building. It’s full of nooks and crannies such that you never really know where you are. It’s got two stories, but it’s hard to say which story you’re standing on at any one time. In one sense, this two-story stuff can be seen as a metaphor for the two William Wilsons. They are inseparable and it’s hard to tell them apart. In another sense, you can see the schoolhouse as a metaphor for the whole story of “William Wilson.” As the reader, we never know where we stand. Is the narrator telling the truth? Where is he narrating from, anyway? Where and when, relative to this story, are we even located?