Vonnegut's parallel to "The Pilgrim's Progress" is deliberate and evident in Billy's surname.

Entity and relation annotations:
id: 0
type: entity
value: text: Vonnegut
labels: <Person>
id: 1
type: entity
value: text: "The Pilgrim's Progress"
labels: <Work_of_art>
id: 2
type: entity
value: text: Bill
labels: <Person>