So far as the difference between an allegory and metaphor is anxious, each manage to belong to exactly the same group of figures of speech. The explanation is each indicate comparison. In his e book In Other Footwear: Songs, Metaphor, Empathy, Existence Kendall Walton also sites the formulation of metaphors https://dallasiotxb.wikihearsay.com/3431497/top_guidelines_of_metafora