void step(int);

void hilbert(int dir, int rot, int order) {

   if (order == 0) return;

   dir = dir + rot;
   hilbert(dir, -rot, order - 1);
   step(dir);
   dir = dir - rot;
   hilbert(dir, rot, order - 1);
   step(dir);
   hilbert(dir, rot, order - 1);
   dir = dir - rot;
   step(dir);
   hilbert(dir, -rot, order - 1);
}