Represent each of the following strategies as an automaton,

a) 4 C then D - Play C in the first four periods, and then D after that, regardless of what the other player does.

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

c) One Lapse Grim - 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. (punishment is grim, but a single lapse is forgiven.)

d) Win-Stay, Lose Shift - This strategy starts by playing C, and repeats their action from the previous period if the other player played C in the last period, and switches actions if the other person played D in the last period.