What metaphors are used in The Defense by Vladimir Nabokov?

In Chapter Twelve, we learn that Petrishchev represents the past from which Luzhin cannot escape. He remembers Luzhin as an awkward, lonely child, who eventually became a chess genius. He also remembers Luzhin as the son of a writer. These are all things that chess allowed Luzhin to escape. Now, as an adult, Luzhin is no closer to understanding the boy he was. This encounter is a metaphorical return to the anxiety of his youth.