public static void drawArrow(Graphics2D g,Polygon arrow,int x,int y){
  arrow.translate(x,y);
  g.draw(arrow);
  g.fill(arrow);
  arrow.translate(-x,-y);
}

public static void drawArrow ( Graphics2D g , Polygon arrow , int x , int y ) { arrow . translate ( x , y ) ; g . draw ( arrow ) ; g . fill ( arrow ) ; arrow . translate ( - x , - y ) ; }
utility function to draw in ( x , y ) one of the polygon used for the arrows
