Goal: connect 4 of your color in a row, horizontally, vertically, or diagonally.

Rules:

- when a square has more than 3 neighbors, it is considered dead. Pieces cannot be placed there anymore.

- if a square becomes dead with a piece in it, the piece is removed.

- when a square is surrounded with more than 2 neighbors of one color, it is restricted to only that color. If the other color is inside, their piece will be removed.