Self-made graphic (loosely influenced by File:San-Tome-Bergamo_(detail).jpg), converted from the following vector PostScript source code:

%!
%.75 dup scale 0 5000 sqrt translate
306 396 translate 18 setlinewidth/z{20000 sqrt}def .96
1 .92 setrgbcolor/w{27}def/y{gsave w 2 mul setlinewidth
0 setgray}def 1 setlinejoin
z .5 mul w add dup neg 100 225 285 arc
w z w add neg 100 -15 45 arc
z .5 mul w add neg z .5 mul w sub neg 100 45 105 arc
w neg w 100 165 225 arc closepath y stroke grestore
stroke w neg z 1 mul w add neg 100 135 195 arc
z .5 mul w add neg dup 100 255 315 arc
w w 100 -45 15 arc
z .5 mul w add z .5 mul w sub neg 100 75 135 arc
closepath y stroke grestore stroke y
-27 27 moveto 54 -54 rlineto stroke
-27 27 z sub moveto 54 -54 rlineto stroke grestore
-28 28 moveto 56 -56 rlineto stroke
-28 28 z sub moveto 56 -56 rlineto stroke showpage
%EOF