Final answer:
Macbeth's entrance after line 16 is an example of dramatic irony, as the audience is privy to Macbeth's treacherous thoughts and intentions, knowledge which other characters in the play are not aware of. This awareness creates tension and emphasizes the tragedy of the unfolding events.
Step-by-step explanation:
Macbeth's entrance after line 16 can be examined for its use of dramatic irony. This literary device occurs when the audience is aware of something that the characters are not. In this case, the dramatic irony arises from the knowledge the audience has of Macbeth's actions and his subsequent mental state following his treacherous deeds, a contrast to the other characters who remain oblivious.
For example, when King Duncan awards Macbeth with the title of Thane of Cawdor for his bravery in battle, he's ignorant of the witches' prophecy and Macbeth's growing ambition. Duncan's statement "No more that thane of Cawdor shall deceive/Our bosom interest: go pronounce his present death,/And with his former title greet Macbeth." underscores dramatic irony, as the audience knows that Macbeth will go on to deceive Duncan in the gravest way possible—by assassinating him.
Moreover, Macbeth's aside in the lines following Duncan's proclamation reveals his internal conflict and contemplation of his dark thoughts, unbeknownst to the other characters. This contrast between audience awareness and character ignorance is at the heart of Shakespeare's use of dramatic irony in advancing the tragic tension of the play.