anchor.diff:      if (!board.isLegalMove(loc, card, playedDir)) {
         return false;
       }
  +    
  +    //TODO add validity check for payment path, if required
   
       board.playCardToStation(loc, card, playedDir, player.playerNum);
   
  
positive.code:   bool playCard(Player player, Card card, BoardLoc loc, CardDirection playedDir,
        [PaymentPath path]) {
      //validity checks
      if (activePlayer != player) {
        return false;
      }
  
negative.code: 
    void makeSelection(Player player, Card card) {
      //TODO allow a player to change selection before all selections are in
      if(roundState != RoundState.make_selections) return;
      
      if (roundData[player.playerNum].hand.contains(card) && getSelection(player) == null) {
        if (selections.containsKey(card)) {
          selections[card].add(player);
  