Final answer:
In "The Fall of the House of Usher," Poe made Roderick and Madeline twins to create mirroring and reflection in their physical appearance and psychological deterioration. This intensifies the theme of doom and adds suspense to the story.
Step-by-step explanation:
In Edgar Allan Poe's story, "The Fall of the House of Usher," Roderick and Madeline are portrayed as twins rather than just brother and sister to create a sense of mirroring and reflection. The twins share a "striking similitude," both in their physical appearance and in their psychological deterioration. This similarity intensifies the theme of doom and hopelessness throughout the story. Additionally, the use of twins allows Poe to create parallelism between the events happening in the story and the events in the romance story that the narrator reads to Roderick, further enhancing the suspense and tension.