1. Represent each of the following strategies for an infinitely repeated Prisoner's Dilemma game in a diagram.

(a) Choose C in period 1 and after any history in which the other player chose C except, possibly, the previous period; choose D after any other history. (That is, punishment is grim, but its initiation is delayed by one period.)

(b) Choose C in period 1 and after any history in which the other player chose D in at most one period; choose D after any other history. (That is, punishment is grim, but a single lapse is forgiven.)

(c) Tit-For-Two-Tat: Choose C in period 1 and after any history in which the other player did not choose D in the previous two periods; choose D after any history in which the other player chose D in the previous two periods.