Gravity is a 2-player, perfect information 4-in-a-row game with a twist - pieces gravitate towards the edges of the 8 x 8 board. - The board begins play empty. - Each player drops a stone on an empty cell. - The gravitation of the board pulls the stone towards the edges until it reaches an edge or an already occupied cell. A player wins when he makes an orthogonal or diagonal 4 in-a-row.