Possible Clues:

• When the witches in 'Macbeth' say 'Double, double toil and trouble'
• When Otello dies in 'Otello'
• When Othello hides to overhear Cassio's boasting
• When 'Double, double toil and trouble' is chanted in 'Macbeth'
• When "eye of newt" is mentioned in "Macbeth"
• When John Proctor confesses in 'The Crucible'
• When 'Ave Maria' is sung in 'Otello'
• When Ophelia makes her last appearance
• When Othello says to Desdemona, "... would thou hadst ne'er been born!"
• When ''eye of newt'' is used