PLOTTO

Copyright (c) 1995 David Smith

The game starts at a large enough hexagonal board with the following setup:

There are also enough stones off board of four different colors (say Black, White, Red and Blue).

MOVE - Players move in turn to place one stone of either color on an empty cell.
However, the dropped stone must be adjacent, at least, to two other stones.
A stone cannot be adjacent to another stone of the same color.
That line may have more than four consecutive stones. There may be other stones beyond either or both ends of the line of four.
GOAL - Wins the player that makes a 4 in-a-row, with stones of his color at both ends (one player has Black and Blue, the other has White and Red).
 
An example

The player that has White can win by dropping a white stone at [1].

This game can easily be played by four. In those cases, there is an extra rule: If a winning line is formed for more than one player in any turn by one of the players, that player wins. If made by any other player, play continues.