[flppshyb] Instantaneous bughouse

A few evolutions of trying to modify bughouse chess into a two-player turn based game, removing the element of time.  (Which arguably ruins the game.)

Evolution 1: A player has just completed a move on one of the boards.  The other player can now reply on that board, reply on the other board if he or she is to play on that board, or pass, which counts as a move.  If both players pass consecutively, then 1 "second" is removed from both game clocks.  A "second" has no relation to actual time passage; it is just a decrementing counter.

The underlying idea is that it simulates both players playing infinitely fast, instantaneously, unless they are explicitly stalling.

Evolution 2: Whoever is losing on the diagonal clock difference is not allowed to pass.

Unfortunately, neither of these work, because the two game clocks always remain in sync, so the diagonal time difference never varies from zero.

Evolution 3: a pass permitted arrow which alternates between players each time a pass is invoked, inspired by the possession arrow in basketball.  (Also similar to the "button" in poker.)  Unfortunately, this does not work, because the players can can pass consecutively, causing the passing arrow to simply alternate 180 degrees out of sync with the passing.

Evolution 4: Some system to trade the privilege of forcing your opponent to make a move now, in return for giving your opponent that privilege some time in the future.  Perhaps not an even trade.  Perhaps an auction system.  Perhaps an arrow or button signifying who has the initiative in the auction.