anchor.diff:    // Expressions.
     //
   
  -  // TODO(bkonyi): swap to use coinFlip()
  -  void emitBool() => emit(rollDice(2) ? 'true' : 'false');
  +  void emitBool() => emit(coinFlip() ? 'true' : 'false');
   
     void emitSmallPositiveInt({int limit = 50, bool includeSemicolon = false}) {
       emit('${choose(limit)}');
  
positive.code:     emitBraceWrapped(emitStatementsClosure);
      emit(' catch (exception, stackTrace) ', newline: false);
      emitBraceWrapped(emitStatementsClosure);
      if (rollDice(2)) {
        emit(' finally ', newline: false);
        emitBraceWrapped(emitStatementsClosure);
      }
  
negative.code:       int classIndex = currentClass;
        // Chase randomly up in class hierarchy.
        while (classParents[classIndex] > 0) {
          if (coinFlip()) {
            break;
          }
          classIndex = classParents[classIndex];
  