"This is the Beach" (metaphor)
When they first arrive onstage, Mommy tells Daddy, "this is the beach," and the audience is led to understand that the stage is meant to represent the beach. The beach and the sandbox on it represent a kind of liminal space, in between life and death. While the stage is not made to look like a literal beach, it represents it.
"Angel of Death" (metaphor)
The Young Man character is an actor playing the Angel of Death in the play. The fact that he doesn't know his name as he hasn't been given one by the movie studio yet represents that he too is a liminal element of the play space, that he represents an intermediary between life and death. He tells Grandma that he is "the Angel of Death," and in taking on that name, he becomes the Angel of Death, making the metaphor literal: he has come to usher Grandma into the world of the non-living.
"Under the Stove" (metaphor)
Grandma says that she was given a place to live with Mommy and Daddy: "under the stove" and with an Army blanket and a dish. While it is unclear whether this is actually where she lives in Mommy and Daddy's townhouse, and whether these are her only possessions, these details become metaphors for her mistreatment in Mommy's house: for Mommy and Daddy's lack of respect for her, and for her loss of identity living with her daughter.
