Visual Metaphor in The Piano Lesson by August Wilson

In The Piano Lesson, metaphors are created through a pattern of reference, mystery, story, and then final effect.  

First, the object must be referenced.  This identification usually takes place physically with the item appearing on stage.  In the case of the piano, it is immediately recognizable from the onset of the play as the most striking object on the stage.
 
Secondly, the object is clouded in mystery.  In this part of the metaphor process, the mechanics of play raise the object above the common by connecting it with passion and the supernatural. 

In the third part of this process, the magical source of the object is revealed by a story.  The play allows us to gain access to the “mystical rites” of object and we are included in the mystery.
 
The final and most important part of Wilson’s metaphor process is the effective utility of the object.  Like a treasure chest filled with gold coins, the object is filled with layers of conflicting meaning until it is used in an unsuspecting yet not unimaginable way.  In The Piano Lesson, the ghost of the past (Sutter) and the threat of the present (Boy Willie) are banished only once the object (piano) is utilized (played in reverence to the past by its protecting sentinel, Berniece).