Bram, the Roshambo strategies you describe sound similar to some of the old Prisoner's Dilemma tournaments i've read about. from Game Theory and Strategy, by Philip D. Straffin:

Axelrod invited professional game theorists to write computer programs to play iterated Prisoner's Dilemma, and then conducted a tournament in which each program played all the other programs. Fourteen programs were entered, some of considerable complexity. The winner was a four line program submitted by Anatol Rapoport, called TIT FOR TAT. Its instructions were:

1. Start by choosing C [cooperate].
2. Thereafter, in each round, choose whatever your opponent chose in the previous round.

In other words, "Do unto your opponent what your opponent has just done unto you."

[...] A more general conclusion comes from Axelrod's analysis of programs which did well. They tended to share four properties with TIT FOR TAT. To do well, a strategy should be

• Nice. It should start by cooperating, and never be the first to defect.
• Retaliatory. It should reliably punish defection by its opponent.
• Forgiving. Having punished defectionn, it should be willing to try cooperating again.
• Clear. Its pattern of play should be consistent and easy to predict.

It is tempting to speculate about the extent to which these four properties might characterize successful social behavior in competitive situations.

not really directly applicable to the Roshambo stuff, but i think it's interesting and you reminded me of it. and game theory is generally just cool.

wow. it's been a long time since i've posted here...