How does O'Casey use stagecraft to support the play's themes?

O'Casey uses a variety of objects in symbolic ways. In Act I, a shovel leans against the dresser, unused due to Boyle's avoidance of work. The mirror and the books by Ibsen on the table represent two opposing forces influencing Mary, her vanity and her desire to better herself through education. In Act II, every available spot is ornamented with huge vases with artificial flowers, symbolic of the extravagance of the Boyles' hopes for the future. The extinguishing of the votive candle is a powerful foreshadowing of Johnny's death in Act III. The removal of the furniture results in an empty room in the last scene, powerfully symbolic of the chaos to which Boyle so often refers.

He uses many stagecrafts to his story.