How does the author use foreshadowing in Mourning Becomes Electra?

In Play I, Act III, an important element of foreshadowing occurs in the stage directions, in which it's made clear that Christine wears a green dress. This foreshadows the green dress that Lavinia wears later in the play, which symbolizes the way in which her physical, spiritual and emotional resemblance to her mother is at its peak. Another element of foreshadowing appears in the reference to Orin's mental state, which foreshadows Orin's continued deterioration and eventual breakdown as the action of the play unfolds.