class Point {
   public double x, y; 
   public static Point origin = new Point(0,0); 
     // This always refers to an object at (0,0) 
   Point(double x_value, double y_value) {
      x = x_value; 
      y = y_value; 
   }
   public void clear() {
      this.x = 0; 
      this.y = 0; 
   }
   public double distance(Point that) {
      double xDiff = x - that.x; 
      double yDiff = y - that.y; 
      return Math.sqrt(xDiff * xDiff + yDiff * yDiff);
   }
}




class Pixel extends Point {
  Color color; 

  public void clear() {
     super.clear(); 
     color = null; 
  }
}