anchor.diff:  
   class Room extends Card {
     const Room._(name):super(name);
  +  const static final List<rOOM> all = [HALL, STUDY, LIBRARY, CONSERVATORY, 
  +  BALL_ROOM, BILLIARD_ROOM, LOUNGE, DINING_ROOM, KITCHEN];
     
     static final Room HALL =
         const Room._("HALL");
  
positive.code:   cards.removeAt(cards.indexOf(winners.room));
    cards.removeAt(cards.indexOf(winners.weapon));
    cards.removeAt(cards.indexOf(winners.character));
    
    return cards;
  }
  
negative.code:       const Room._("LIBRARY");
    static final Room CONSERVATORY =
        const Room._("CONSERVATORY");
    static final Room BALL_ROOM =
        const Room._("BALL_ROOM");
    static final Room BILLIARD_ROOM =
        const Room._("BILLIARD_ROOM");
    static final Room LOUNGE =
        const Room._("LOUNGE");
    static final Room DINING_ROOM =
        const Room._("DINING_ROOM");
    static final Room KITCHEN =
        const Room._("KITCHEN");
  }
  
  class Weapon extends Card {
    const Weapon._(name):super(name);
    const static final List<Weapon> all = [KNIFE, CANDLESTICK, PIPE, PISTOL, ROPE, POISON];
    
    static final Weapon KNIFE =
        const Weapon._("KNIFE");
    static final Weapon CANDLESTICK =
  