Allan Gray is an unseen, yet omnipresent character, the late husband of Blanche Dubois and a vital part of her back-story rather than a main, physical character in the play.
Williams employs Plastic Theatre, the use of props, sound and stage directions to relay obvious parallels with a character’s state of mind, to symbolize Allan’s omnipresence.
Williams builds the tension and reveals only at the end of Blanche’s monologue that Allan broke away from her and killed himself because she rejected his sexuality.
The Varsouviana Polka is the song that was playing when Allan killed himself and Blanche hears this sound in her head till a gunshot sounds whenever she is feeling stressed.
The audience and Blanche are the only ones who hear this song while the other characters cannot, dramatic irony, it serves as a reminder of her past and deteriorating state of mind.
Stanley's dialogue in Scene 8 is interrupted by Steve and Eunice to show what Stanley and Stella's marriage will revert to and to depict their wedded bliss.
The more Stanley comes closer to destroying Blanche, the worse her mental stability becomes and this deterioration is reflected in her mentions of Shep Huntleigh.
Williams introduces desire as the opposite of death, using the incident of young soldiers staggering onto Blanche's lawn on Saturday nights to get drunk.
Blanche's attitude and approach toward the young man reflect all her past affairs with young soldiers and boys, including the 17-year-old student in her school.
In Scene 5, Blanche touches the young man's cheek lightly and smiles, then takes a large, gossamer scarf from the trunk and drapes it about her shoulders.
The Mexican flower-seller appears on Blanche's doorstep, saying "Flores para los Muertos," which translates to "Flowers for the dead," frightening Blanche and causing her to relive her grim past.