PROGRAM

  ROUTINE trace
  BEGIN
    FORWARD 70;
    ROTATE 160;
  END

  ROUTINE trace3
  BEGIN
    CALL trace;
    CALL trace;
    CALL trace;
  END

BEGIN
  FORWARD 200;
  ROTATE 90;
  FORWARD 300;
  ROTATE 270;
  PEN DOWN;
  CALL trace3;
  CALL trace3;
  CALL trace3;
END.