This Demonstration shows a two-person game between you and an imaginary adversary. A move consists of choosing or in order through , , , . Each such choice eliminates (shown by shading) all corresponding numbers in the bottom row.[more]
The game starts at the root with no number eliminated. You get first move. You may choose or , then or , and so on. Before making a move, you first must ask your adversary whether he wants to choose (unless he has already chosen twice in a row). If he does not, you can choose. Your aim is to get as high a number as possible. The aim of your adversary is that you get as small a number as possible. Without an adversary, you can play for both sides.[less]
Adversarial bifurcation games are described in [1, pp. 81–86].
 D. E. Shasha, Puzzling Adventures, New York: W. W. Norton & Company, 2005.