draw a rosette:
   enter turtle graphics;
   go to the centre;
   UPTO 6
   REP draw equilateral hook;
   turn (60)
   ENDREP;
   wait for confirmation (10, 10);
   leave turtle graphics.


go to the centre:
   REAL CONST d:: turtle y limit / 3.0;
   move (turtle x limit / 2.0, turtle y limit / 2.0).


draw equilateral hook:
   draw (d); turn (120);
   draw (d); turn (120);
   move (d); turn (120).