As it was at the end of class

#include "library.h"

void specialline(double len)
{ if (len<=1)
    draw_distance(len);
  else
  { specialline(len/3);
    turn_left_by_degrees(60);
    specialline(len/3);
    turn_right_by_degrees(120);
    specialline(len/3);
    turn_left_by_degrees(60);
    specialline(len/3); } }

void main()
{ make_window(700, 700);
  move_to(20, 580);
  set_heading_degrees(30);
  specialline(550);
  turn_right_by_degrees(120);
  specialline(550);
  turn_right_by_degrees(120);
  specialline(550);
  turn_right_by_degrees(120); }


Now made slightly more flexible


#include "library.h"

void specialline(double len)
{ if (len<=1)
    draw_distance(len);
  else
  { specialline(len/3);
    turn_left_by_degrees(60);
    specialline(len/3);
    turn_right_by_degrees(120);
    specialline(len/3);
    turn_left_by_degrees(60);
    specialline(len/3); } }

void specialstar(double size)
{ const double pi = acos(-1.0);
  const double h = size/cos(30*pi/180);
  specialline(h);
  turn_right_by_degrees(120);
  specialline(h);
  turn_right_by_degrees(120);
  specialline(h);
  turn_right_by_degrees(120); }

void main()
{ make_window(700, 700);
  move_to(20, 580);
  set_heading_degrees(30);
  specialstar(600); }