Symbol: The Wall
A wall is a symbol of separation, of closing oneself off or being closed off from someone or something. It suggests a fortress or a prison, a barrier that is not easily surmounted. The literal wall that the husband and wife have built for their home is a way to close them off from potential burglars and "bad" people, but it is also a powerful symbol of how they do not want to mix with the Other in any capacity. The wall between the family and those beyond is indeed insurmountable, as they have fully embraced racist and classist thinking as a means of understanding themselves in the world.
Symbol: Barbed Wire
The barbed wire coils are a symbol of prison and of a concentration camp, the latter of which the text itself even explicitly identifies. The serrated coils are indicative of a desire to keep people out and keep people in; they are utilitarian but vicious. They signify the extreme move away from considering the humanity of others and the extreme separation of people.
