How does the author use foreshadowing in No Exit?

In the first scene, the characters' references to their deaths, their relationships, and their lives all offer hints about their respective stories..... the actions that brought them to hell. These hints foreshadow the dramatic action of the play, as they reveal each of the characters' layers of bravado, defensiveness and confidence, as they're peeled away until we see their respective truths.

Another aspect of foreshadowing is the reference to the paper knife, which foreshadows the scene where Inez stabs herself repeatedly, proving she cannot be killed again. A third aspect of foreshadowing can be found in the repeated mention of torture, which suggests the torture each of the characters will put the other through over the course of the play.