Edgar Allan Poe's central dictum of the short story is that it must contain a singleness derived from pattern and design throughout the harrative, an arabesque, as it is termed, that follows what one critic calls "the principle of redundancy and repetition." Moreover, since the narrators of many of his stories are obsessed, what obsesses them is, then, repeated and patterned throughout the narrative.
Indeed, it is this pattern which gives significance and unity to the separate elements of the story. No cause and effect narratives are Poe's works; instead, Poe maintains that the reader must become aware of the "end" of the story and its main intent early on in order to grasp the overall purpose and understand that the "seemingly trivial elements" actually have significant meaning in this total pattern.
In this story, the motif of the eye generates the focus of the narrator's obsession that drives the narrative to its single effect. The narrator identifies with the old man, yet proclaims that he hates his "Evil Eye." Obsessed with this vulture-like eye, the narrator repeats observations about the eye as he peeks at it for seven nights. But, in his identification with the old man, the narrator is unwittingly sympathetic to the man's listening to the death watches.
Meantime the hellish tattoo of the heart increased....The old man's terror must have been extreme! It grew louder, I say, louder every moment! ... I have told you that I am nervous; so I am....amid the dreadful silence...so strange a noise as this excited me to uncontrollable terror.
In his efforts to escape "the curse of time and mortality" symbolized by the "hellish tattoo" of the heart and the morbidity of the"vulture eye," the narrator kills the "eye" as he would like to halt the torture of his own "I." Later, however, what the murderer perceives as the ticking of the old man's heart is, in fact, the ticking of his own heart in his identification with him as a mortal cursed--the principle of "redundancy and repetition."
With his poem, Poe expressed a wish to create an effect of beauty with melancholy; he felt that the word "Nevermore," repeated with differing circumstances and impact, lent a melancholic echo to the narrator's sorrow. This "redundancy and repetition" evokes the theme of what Poe perceived as the universal need in humans for self-torture:
On the morrow he will leave me, as my Hopes have flown before.
Then the bird said "Nevermore."
The use of arabesquein this story is proliferate as every single detail contributes to the final ironic effect of the narrative. Continually, Montresor ironically admonishes Fortunato not to continue into the catacombs because the niter will harm him. But, the greatest irony is that Fortunato avenges himself on Montresor, and Motresor has not gotten away with impunity and Montresor has not gotten away with impunity because in telling his story fifty years later, he exhibits his guilt and must be making a confession that cannot be forgiven as it is insincere:
My heart grew sick--on account of the dampness of the catacombs.