docs: private void drawArrow(Graphics g, Point head, Point away) {
  		int endX, endY;
  		double angle = Math.atan2((double) (away.x - head.x),
  				(double) (away.y - head.y));
  		angle += ARROW_ANGLE;
  		endX = ((int) (Math.sin(angle) * ARROW_LENGTH)) + head.x;
  		endY = ((int) (Math.cos(angle) * ARROW_LENGTH)) + head.y;
  		g.drawLine(head.x, head.y, endX, endY);
  		angle -= 2 * ARROW_ANGLE;
  		endX = ((int) (Math.sin(angle) * ARROW_LENGTH)) + head.x;
  		endY = ((int) (Math.cos(angle) * ARROW_LENGTH)) + head.y;
  		g.drawLine(head.x, head.y, endX, endY);
  	}