Consider the centipede game that is described in the figure below. It has two players, A and B, and four stages:
Stage 1: Player A has two piles of cash, one with $4 and the other with $1. Player A has two choices to terminate the game, taking the larger pile $4 and giving the smaller pile $1 to player B, or pass both piles to player B. If player A terminates, the game is over. If player A passes, the game moves to stage II.
Stage II: The money in both piles doubles, and player B has two choices, either pass (ps) or terminate (t). If player B chooses to terminate, the game ends at stage II. If player B passes, the game moves to stage III.
Stages III-V: The money in both piles doubles at each stage. The game ends at stage IV.
Determine the sub-game perfect Nash equilibrium (SPNE) for this game. Note that the bold payoff goes to player A.