What metaphors are used in Three Plays by Eugene O'Neill?

The value of the house in "Mourning Becomes Electra" is entirely metaphorical, and functions on a few different levels. The first creates a resemblance to Classical Greek theatre, which was almost always set outside, and specifically the outside of a temple or palace. This, in turn, is related to the origins of this sort of theatre in ancient religious/spiritual festivals. The fact that much of the action of takes place within the mansion is, like the ways in which the characters and stories of the play diverge from the original, metaphorically relevant. Because the house itself is a metaphor for the "edifice" of hatred and revenge the Mannon family has constructed for itself, the fact that much of the action takes place within the house suggests that that action is itself contained within the oppressive confines of that revenge.