Final answer:
The poetic device used in the line 'The sky folds its wings over you' is personification, which assigns human attributes to non-human subjects to create vivid imagery.
Step-by-step explanation:
The poetic device used in the line 'The sky folds its wings over you' is personification. Personification is a figure of speech in which a thing, an idea or an animal is given human attributes. In this example, the sky is depicted as having wings and the ability to fold them, which are human-like actions, thus bringing the sky to life in the reader's imagination. In poetry, personification adds depth and emotion to the description, helping to create a more vivid image in the mind of the reader. Personification is used alongside other figurative language tools such as metaphor, simile, and hyperbole to enrich the text and provide insight into the poet's vision.