Unlike the barren stage of Shakespeare and the Elizabethans, modern and contemporary drama is noted for the use of advanced stage probes. In Death of a Salesman, Arthur Miller uses many probes to emphasize the main ideas in the play and to help the audience identify the shift in time from the present to the past and vice versa. Among the techniques used are light and darkness, music, transparent walls, and special techniques for the flashbacks. In The Great God Brown, Eugene O'Neil uses masks to reflect the inner sides of the characters.