prologues := 2 ;
defaultfont := "cmr10" ;

beginfig(1)

    numeric l ;

    l = 500 ;

    z0 = (0,0) ; z4 = (l,0) ;
    z1 = 1/3[z0,z4] ; z3 = 2/3[z0,z4] ;
    z2 - z1 = (z3 - z1) rotated 60 ;

    def next(expr p) =
        (p scaled 1/3) -- (p scaled 1/3 rotated 60 shifted z1)
          -- (p scaled 1/3 rotated -60 shifted z2) -- (p scaled 1/3 shifted z3)
    enddef ;

    path etoile ;

    etoile = (0,0) -- (l,0) ;

    for i = 1 upto 5 :
        etoile := next(etoile) ;
    endfor

    z4 - z0 = (z5 - z0) rotated 60 ;

    draw etoile -- (etoile rotated -120 shifted z4) -- (etoile rotated 120 shifted z5) ;
    draw (etoile yscaled -1) -- (etoile yscaled -1 rotated -120 shifted z4)
                   -- (etoile yscaled -1 rotated 120 shifted z5) ;

endfig ;

end