Another example: https://en.wikipedia.org/wiki/Live_and_let_live_(World_War_I) https://en.wikipedia.org/wiki/Live_and_let_live_(World_War_I... This example was

Another example: https://en.wikipedia.org/wiki/Live_and_let_live_(World_War_I) https://en.wikipedia.org/wiki/Live_and_let_live_(World_War_I... This example was discussed in Robert Axelrod's "The Evolution of Cooperation".