Here's why the repetition is so impactful:
* Emphasis on the Act: The repetition of "hung it" emphasizes the brutal and senseless act of the narrator hanging his beloved cat. It highlights the escalating violence and cruelty that he inflicts upon the animal, foreshadowing his eventual violence against his wife.
* The Narrator's Guilt: The repetition of the phrase also serves as a reminder of the narrator's growing guilt and regret. He acknowledges the wrongfulness of his actions but is unable to escape the cycle of violence that he has created.
* Building Tension: Each repetition of the phrase increases the tension and suspense, building toward the climax of the story and the narrator's final act of violence.
* Creating a Disturbing Rhythm: The repeated phrase also creates a disturbing and unsettling rhythm, mirroring the narrator's fragmented and erratic mental state.
The repetition of "hung it" is a key element in Poe's masterful use of language to explore the themes of guilt, madness, and the destructive power of violence. It effectively underlines the narrator's descent into depravity and the tragic consequences of his actions.