The entrancing, hynotic repetition and rhyming couplets shows that the witches are presented as the archetype of the supernatural with their malevolent and entrancing powers. it reinforces how theyre casting these intentionally decietful and hypnotic spells to further decieve macbeth because of his hubris. fire creates an image of irreversible damage; this foreshadows the irreversible damage that will be caused to macbeth, aka his downfall.