Own work -- Converted from the following vector PostScript source code:

%!
306 326 translate 17.5 setlinewidth 1 setgray
/y{gsave 42 setlinewidth 0 setgray}def/x
15.6434465 def/w 10.60519935 def
/m{moveto}def/l{lineto}def 180 200 m
100 x add 100 x add 100 x sub 90 270 arc
0 0 170 w 180 w sub arc
100 x add neg 100 x add 100 x sub 270 90 arc
-180 200 l y stroke grestore stroke 180 -200 m
100 x add 100 x add neg 100 x sub 270 90 arcn
0 0 170 360 w sub 180 w add arcn
100 x add neg 100 x add neg 100 x sub 90 270 arcn
-180 -200 l y stroke grestore stroke
gsave 1 setlinejoin
-160 -200 m -200 -200 l 200 200 l 160 200 l
42 setlinewidth 0 setgray stroke
-159 -200 m -200 -200 l 200 200 l 159 200 l
17.5 setlinewidth 1 setgray stroke
-160 200 m -200 200 l 200 -200 l 160 -200 l
42 setlinewidth 0 setgray stroke
-159 200 m -200 200 l 200 -200 l 159 -200 l
17.5 setlinewidth 1 setgray stroke
grestore 6 setlinewidth
0 0 194 w neg w arc stroke
0 0 194 180 w sub 180 w add arc stroke
12.25 setlinewidth 0 setgray
0 0 184.875 w neg -4 arc stroke
0 0 184.875 4 w arc stroke
0 0 184.875 180 w sub 176 arc stroke
0 0 184.875 184 180 w add arc stroke
1 setgray y
100 x add neg 100 x add 100 x sub 271 -1 arc stroke
100 x add 100 x add neg 100 x sub 179 91 arcn stroke
0 0 170 31 59 arc stroke
0 0 170 211 239 arc stroke
0 0 170 91 119 arc stroke
0 0 170 271 299 arc stroke
100 x add neg 100 x add neg 100 x sub -89 -1 arc stroke
100 x add 100 x add 100 x sub 91 179 arc stroke
grestore 17.5 setlinewidth
100 x add neg 100 x add 100 x sub 270 0 arc stroke
100 x add 100 x add neg 100 x sub 180 90 arcn stroke
0 0 170 30 60 arc stroke
0 0 170 210 240 arc stroke
0 0 170 90 120 arc stroke
0 0 170 270 300 arc stroke
100 x add neg 100 x add neg 100 x sub -90 0 arc stroke
100 x add 100 x add 100 x sub 90 180 arc stroke
%EOF