What are three examples of dramatic irony in macbeth speeches to banquo

In the royal palace at Forres, Banquo paces and thinks about the coronation of Macbeth and the prophecies of the weird sisters. The witches foretold that Macbeth would be king and that Banquo's line would eventually sit on the throne. If the first prophecy came true, Banquo thinks, feeling the stirring of ambition, why not the second