EDIT three years later, the images went away, so I replace them.
I believe the poster roundabout2 is in fact Michael Katz, who is Alex Randolph's nephew. I am pleased to report that differences between Mr. Katz and Mr. Dolezal have been mostly resolved. They are now working together to bring Twixt to the market in 2018. I have invited both of them to participate in this thread.
So, I hope it is appropriate now to mention some possible issues with implementing Twixt on BGA. You can read the rules of Twixt on
Wikipedia and on the
Twixt Wiki. Twixt is already available for real time play on
Game Center and turn-based on [url=hhttps://
www.littlegolem.net/jsp/games/gamedetail.jsp?gtid=twixt]Little Golem[/url] (actually a variant called TwixtPP) and on
Gamerz as well as other servers.
automatic linking
This is a convenience which makes the game interface much easier for players. Whenever a peg is placed on the board, all legal links to that peg are automatically added by the server. All the Twixt servers I know, with the single exception of the
Vassal Twixt module, use autolinking. Everyone is used to it, and to my knowledge no user has ever complained about it.
But strictly speaking, this could be regarded as a rules modification. It is, after all, the player's responsibility to add links, not the computer's. I could offer an alternative game setting where both players would have to manually add each link to the board. This would
not be the default setting. Anyone who joins such a game should probably be warned that manual linking is invoked, through a popup window that they would have to click OK on before the game starts. But I doubt that two people would ever both deliberately choose to play this way. I would particularly like to know from Mr. Katz if autolinking would be acceptable.
resolving drawn positions
One criterion for implementing a game on BGA is, the game must end. Sometimes in Twixt, one player has blocked the other from any possible winning path, but has not himself formed a continuous chain, and is blocked from doing so. You can see a contrived example
here and an actual agreed draw
here. As far as I know, all the other servers deal with this issue by allowing players to propose and to accept a draw. So far, this has worked well.
But what would happen if one player refuses to agree to a draw? Would the game continue for 572 moves? Then what would happen? I have to code the server to recognize a draw. If, at the start of a player's move, all possible winning paths for the opponent have been blocked, a button should appear "claim draw" which would allow that player to end the game as a draw without the opponent's permission. Of course the player should not click this button if there is a win available.
If, at the end of a player's move, both sides are blocked from any winning path, the server should end the game and declare it a draw. This has not been necessary so far on any server because players strong enough to achieve a draw have also been strong enough to agree to a draw before all possible winning paths for both sides have been blocked.
Consider these two examples on a small grid.
The server should claim a draw here. The only winning path for the light color pieces would cross over itself, which is allowed in TwixtPP, but is not possible with a physical set and is not allowed under standard rules.
Here a button should be available to the light color to claim a draw, but that player can win by simply removing the H4-J3 link and adding a link from H3 to i5. So, here's my question.
How should the server resolve this game if the light player refuses to claim a draw or accept a draw offer, and refuses to win by rearranging links?