Article date: Jul 1962
Article title: Fiction about life in two dimensions
Mathematical Games column? Y
Book: 5. The Unexpected Hanging and Other Mathematical Diversions
Chapter: 12. Flatlands
This data confirmed? yes
Notes
Peter Rowlett (27 August 2022):
Peter Rowlett initial guess (Uncertain)
Peter Rowlett (29 October 2023):
I have seen this chapter and column side-by-side and they match.