A simple game for two players, by Lloyd.
The Game Components
The board has twenty-five spaces on it, arranged in a five-by-five square, in neat rows. Each player has a set of twelve playing pieces, easily distinguished from the opponent's. Some method of keeping score is needed. One method is to have a supply of more playing pieces, and for a player to pick another one of his colour/type every time he scores a point, and to keep these by him in a pile.
The Placing Stage
The game starts a bit like a cross between Go and Connect Four. The taller player goes first, and the first turn alternates for subsequent games. If both players are the same height, then the player with the greater shoe size goes first. A further tie is decided with a fist fight. The advantage of going first is so tiny, that it really isn't worth making a fuss over. The first player places one piece on any space on the board. Play then alternates with each player placing down one more piece on any unoccupied space, until both players have placed twelve pieces. All but one of the board's spaces will now be filled.
A player scores one point if he can place four pieces in a line, which may run along any row or column, or along any diagonal. If he adds another piece to a line of four, making a line of five, then he scores another point. If he places a piece in the middle of a broken line of his own pieces, thereby creating a line of five when before there was no line of greater than three, he scores two points.
The Movement Stage
Once all the pieces have been played, the player who did not go first at the placing down stage of the game takes the first move. If he would create a line of four or five by placing a piece down in the one gap left on the board, then he may miss his turn and take the point(s) for this instead (in which case the player who placed the first piece would move first), otherwise, he makes the first move. That he may score this way, and that he may otherwise make the first move, counteracts the advantage of placing the first piece.
The movement stage is a bit like Nine Mans' Morris and a bit like those sliding puzzles where you have to shuffle tiles around to make a picture.
To move a piece, a player selects any piece which is next to the one gap on the board, and moves it into the gap, creating a new gap. Pieces move along rows and columns only, and not on the diagonal. The players alternate turns. A player may not select the piece which was moved last by the other player, and must instead move a piece which was not moved last turn. He may select a piece of either colour/type to move, and not just those of his own. If the gap is in a corner, then the player will have no choice of which piece to move, and is forced to use his turn moving whatever piece was not moved last.
Scoring in the movement stage of the game is the same as for the placing stage. Players try to form lines of four or five along the rows, columns, and diagonals of the board. If a player creates a line of his opponent's pieces, then his opponent scores as usual. The first player to reach an agreed score wins. Twelve is a good number to aim for.
In the placing stage, players may sacrifice opportunities for scoring, in order to get good groupings of pieces which will be useful in the movement stage of the game. Very often, a point is scored by forcing the opponent to move one of your pieces to create a line for you.