Here is a version of the tibit game with two players, called “trickster” and “webster”.
The webster is the first player. The trickster is the second player.
The webster manipulates (i.e. modifies) a “web”, which is a
- trivalent graph
- with oriented arrows
- with a cyclic orientation of arrows around any node (i.e. locally planar)
- it may have free arrows, i.e. ones with free tail or free tip.
Tokens. The webster has one type of token, called a “termination token”. The trickster has two types of tokens, one yellow, another magenta.
Moves. When his turn comes, any player can do one of the moves listed further, or he may choose to pass.
Some of the webster moves are “reversible”, meaning that the webster may do them in both direction. Let’s say that the “+” direction is the one from left to right in the graphical moves and also means that the webster may put a termination token (but not take one). The “-” direction is from right to left in the graphical moves and also means that the webster may take a termination token (but not put one).
The loop rule. It is possible that, after a move by one of the players, the web is no longer a trivalent graph, because a loop (an arrow which closes itself, without any node or token on it) appears. In such a case the loop is erased before the next move.
This is a collaborative game.
There are two webs, with tokens on them, the first called the “datum” and the second called the “goal”.
The players have to modify the datum into the goal, by playing collaboratively, in the following way.
The game has two parts.
Preparation. The players start from a given web with given tokens placed on it (called the “datum”). Further, the webster builds a web which contains the datum and the trickster places tokens on it, but nowhere in the datum .
Eventually they obtain a larger web which contains the datum.
Alternatively, the players may choose an initial web, with tokens on it, which contains the datum.
Play. Now the webster can do only the “+” moves and the trickster can’t put any token on the web. The players try to obtain a web, with tokens on it, which contains the goal by using their other moves.