anchor.diff:  
   let GrantAdvantage p =
       match p with
  -    | Serving -> (DeuceScore AdvantageServing)
  -    | Receiving -> (DeuceScore AdvantageReceiving)
  +    | Serving -> DeuceScore AdvantageServing
  +    | Receiving -> DeuceScore AdvantageReceiving
   
   let ResolveDeuce p s =
       match s with
       | Deuce -> GrantAdvantage p
       | _ when HasAdvantage p s -> DeclareWinner p
  -    | _ -> (DeuceScore Deuce)
  +    | _ -> DeuceScore Deuce
   
   let PointFor (p : Player) (s: TennisScore) : TennisScore =
       match s with
       | DeuceScore d -> ResolveDeuce p d
       | NormalScore n when (n.[p] = Forty) -> DeclareWinner p
       | NormalScore n -> NormalScore (n.Add(p, ScoreSucc n.[p])) |> PossiblyDeuce
  -    | GameOver w -> s+    | GameOver _ -> s
positive.code:     | Thirty -> Forty
      | Forty -> failwith "Succ Forty is not a normal score!"
  
  let StartGame = NormalScore ([Serving, Love; Receiving, Love] |> Map.ofList)
  
  let PossiblyDeuce n =
      if n = (NormalScoreOf Forty Forty) then DeuceScore Deuce
  
negative.code: 
  let DeclareWinner p =
      match p with
      | Serving -> GameOver ServingPlayerWon
      | Receiving -> GameOver ReceivingPlayerWon
  
  let HasAdvantage p s =
      match p with
  