From: Oyun: A New, Free Program for Iterated Prisoner's Dilemma Tournaments in the Classroom
B: Cooperate
B: Defect
A: Cooperate
3, 3 (mutual cooperation)
0, 5 (“sucker's payoff”)
A: Defect
5, 0 (defector's payoff)
1, 1 (mutual defection)