class Scene {
  
  int HEIGHT = 400;
  int WIDTH = 1071;
  
  Drawable[] objects;

  boolean started;
  boolean crashed;

  Scene() {
    objects = new Drawable[0];  
    started = false;   
    crashed = false;
  }

  void registerObject(Drawable obj) {
    objects = (Drawable[]) append(objects, obj);
  }

  void draw() {
    for(int i = 0; i < objects.length; i++) {
      if (started) {
        if (objects[i] instanceof Movable) ((Movable) objects[i]).move();
        if (objects[i] instanceof Manipulable) ((Manipulable) objects[i]).manipulate();
      }
      objects[i].draw();
    } 
  }
  
  void toggle() {
     if(started) stop();
     else start(); 
  }
  
  void stop() {
     started = false; 
  }
  
  void start() {
     started = true; 
     if(crashed) {
       crashed = false;
     }
  }
  
  void crash() {
      stop();
      crashed = true;
  }
  
}