What was Poe thinking?

It was only upon taking a second look at The Cask of Amontillado that I realized how many illustrations of irony Poe placed throughout the story. An example of irony I missed during my first reading was when Fortunado begins coughing uncontrollably and Montressor tells him to leave the catacombs. Fortunado refuses and says, "...I shall not die from a cough." These words are chilling because we know that he will eventually die. The part of the story when Montressor pulls out a trowel as a sign of his being a mason also has a gruesome quality, the importance of which I did not catch the first time I read the story. Finally, giving Montressor the moto Nemo me impune lacessit is a brilliant way to foreshadow Fortunado's impending doom and add to the element of suspense already present.

I wondered about whether Poe intended the reader to recognize the value of these instances during the first reading. I also wondered about the method he used to put so many devices in his stories and pull them together so they make sense at the end. Did he have irony, tones, foreshadowing, structure, ect. planned before he began writing, or did he insert them into his works later? No one can fully appreciate Poe's stories without careful study. After some exploration of The Cask of Amontillado, I have a sense of awe at Poe's command of the English language and mastery of the art of fiction.