Though Act III, Scene 3 of Shakespeare's Macbeth is short, it has some remarkable structural and linguistic devices at play that are worth examining. The component I want to focus on is the regular rhyming pattern used within the dialogue, as it is both a linguistic and structural device that lends considerable rhythm to the text. As an example, check out the first six lines of the scene:
But who did bid thee join with us?
He needs not our mistrust, since he delivers
Our offices and what we have to do
To the direction just.
Then stand with us.
As you can see, Shakespeare utilizes a repeated rhyme within the murderers' dialogue to create a poetic rhythm and pattern. This decision is both linguistic and structural because it ties the language of the scene more closely together, making the violent event to come (Banquo's murder) more compact and ruthless. Indeed, the brutal events of the scene are hauntingly juxtaposed by the murderers' rhythmic, poetic language.
Shakespeare uses a similar linguistic and structural device when he depicts the Weird Sisters. Just as the murderers' dialogue is glued together by regular rhymes, so too is the witches' conversation ordered by a poetic, rhyming pattern. Throughout the play, Shakespeare used tightly crafted poetry to hint at (and juxtapose) the dark deeds and the villainous sides of human nature.