Self-made graphic, generated from the following vector PostScript source-code:

%!306 396 translate 1.7 dup scale/x 77.9423 def/z 30000 sqrt def/D{.87 .87 .96setrgbcolor}def/A{81.6871 -55 36 130 90 arcn z x sub -55 36 90 30 arcn z xsub -55 36 30 -180 arcn z 149.9422 sub -55 36 0 300 arc 6.3608 -19.7249 75300 70 arc 13.6624 dup neg 2.74747742 mul exch rlineto stroke}def/B{gsave A120 rotate A 120 rotate A grestore}def 24 setlinewidth D B 18 setlinewidth 0setgray B 6 setlinewidth 1 setlinejoin x -2 div 200 x 3 sqrt 2 div mul submoveto 0 200 lineto x 2 div 200 x 3 sqrt 2 div mul sub lineto gsave D strokegrestore 0 150 lineto fill z x sub -100 moveto z -100 lineto x -2 div x 3sqrt 2 div mul rlineto gsave D stroke grestore z 1875 sqrt sub -75 linetofill z neg x add -100 moveto z neg -100 lineto x 2 div x 3 sqrt 2 div mulrlineto gsave D stroke grestore z neg 1875 sqrt add -75 lineto fill 0setlinejoin/C{18 setlinewidth 0 setgray z x sub -55 36 40 -100 arcn stroke24 setlinewidth D 6.3608 -19.7249 75 348 8 arc stroke z x sub -55 36 -137-180 arcn z 149.9422 sub -55 36 0 20 arc stroke z 149.9422 sub -55 36 185235 arc stroke 18 setlinewidth 0 setgray z x sub -55 36 -136 -180 arcn z149.9422 sub -55 36 0 21 arc stroke 24 setlinewidth D 81.6871 -55 36 128 130arc 15.2 dup -1.1917536 mul exch neg rlineto stroke 18 setlinewidth 0setgray 6.3608 -19.7249 75 347 9 arc stroke z 149.9422 sub -55 36 184 236arc stroke 81.6871 -55 36 127 130 arc 15.25 dup -1.1917536 mul exch negrlineto stroke}def gsave C 120 rotate C 120 rotate C grestore showpage%EOF