Final answer:
Westley beats Vizzini by poisoning both glasses of wine with iocane powder and relying on his built-up immunity to the poison, leading to Vizzini's death when he drinks from the glass he chooses.
Step-by-step explanation:
The question "How does Westley beat Vizzini?" relates to a scene from the novel or movie 'The Princess Bride.' In this scene, Westley, also known as The Man in Black, defeats Vizzini in a battle of wits. Westley challenges Vizzini to a game where they will drink wine, one glass of which is poisoned. Vizzini must choose which glass to drink from, with the intent that Westley will drink from the other.
Westley outsmarts Vizzini by poisoning both glasses of wine with odorless and tasteless iocane powder. However, Westley has spent years building up an immunity to iocane powder. Vizzini, underestimating Westley, switches the glasses when Westley is not looking and then drinks from the glass he ended up with, believing he has tricked Westley. However, since both glasses are poisoned, Vizzini collapses and dies, regardless of the switch.