[1]https://www.wired.com/story/the-legacy-of-math-luminary-john-conway-lost-to-c
ovid-19/

   Jim Bell's comment:

   Apparently he wasn't surrounded by a sufficient number of occupied
   squares.

References

   1. https://www.wired.com/story/the-legacy-of-math-luminary-john-conway-lost-to-covid-19/