public Position next(Move move) {
		switch (move) {
			case NORTH:
				return row > 0? new Position(row-1, col) : null; 
			case SOUTH:
				return row < Board.SIZE - 1? new Position(row+1, col) : null; 
			case WEST:
				return col > 0? new Position(row, col-1) : null; 
			case EAST:
				return col < Board.SIZE - 1? new Position(row, col+1) : null; 
		}
		return null;
	}