anchor.diff:        _physicsEngine = null;
         return false;
       }
  +    if(gravity == null) gravity = _gravity;
       _physicsEngine._initialize(gravity);
       return true;
     }
  
positive.code: part of orange;
  
  
  abstract class Scene {
    static int FOGMODE_NONE = 0;
    static int FOGMODE_EXP = 1;
    static int FOGMODE_EXP2 = 2;
  
negative.code:     _transparentMeshes.clear();
    }
  
    void enter() {
      
    }
  
    // TODO remove parameters
    void enterFrame(num elapsed, num interval) {
  
    }
  