Article date: Oct 1968
Article title: MacMahon's color triangles and the joys of fitting them together
Mathematical Games column? Y
Book: 8. Mathematical Magic Show
Chapter: 16. Colored Triangles and Cubes
This data confirmed? yes
Notes
Peter Rowlett (27 August 2022):
Peter Rowlett initial guess (Uncertain)
Peter Rowlett (30 October 2023):
I have seen this chapter and column side-by-side and they match.