Andy’s purchase of rock-blankets suggests he’s polishing the rocks he finds, exercising his agency to create beautiful things in the miserable Shawshank environment. At this point, readers realize the narrator has misled them—though perhaps not directly—when he said he smuggled Rita Shawshank into prison. In fact, he smuggled a poster
of her. Thus, from the moment the pin-up posters are introduced, they are associated with misdirection. The narrator seems to be amused by Andy’s furtive demeanor because he thinks Andy’s embarrassed about using the poster as a visual aid to sexual fantasies—but Andy never explains his motives, leaving readers to wonder whether the narrator has misinterpreted Andy. That the narrator sells to Andy “wholesale,” meanwhile, betrays the narrator’s fondness for Andy and their growing friendship.