Self-made image, converted from the following vector PostScript source code:

%!
306 396 translate .6 dup scale/x 31250 sqrt def .16 .82 .16 setrgbcolor
x 2 mul 75 sub 50 50 90 0 arcn x 2 mul 25 sub 0 lineto x 5000 sqrt add
25 25 270 225 arcn x 25 25 45 90 arc 25 50 lineto 125 -50 100 180 270
arc x 2 mul 125 add -150 lineto x 2 mul 125 add 150 lineto x 2 mul 25
add 0 150 90 135 arc 25 0 100 315 270 arcn x -2 mul 75 add -50 50 270
180 arcn x -2 mul 25 add 0 lineto x 5000 sqrt add neg -25 25 90 45 arcn
x neg -25 25 225 270 arc -25 -50 lineto -125 50 100 0 90 arc x -2 mul
125 sub 150 lineto x -2 mul 125 sub -150 lineto x -2 mul 25 sub 0 150
270 315 arc -25 0 100 135 90 arcn closepath gsave 0 setgray 100 3 div
setlinewidth stroke grestore 100 6 div setlinewidth stroke -25 0 150 90
135 arc x -2 mul 25 sub 0 100 315 270 arcn x -2 mul 75 sub -100 lineto x
-2 mul 75 sub 100 lineto -125 50 50 90 0 arcn -75 0 lineto x neg 1250
sqrt 14.644661 sub add 25 25 270 225 arcn x neg 1250 sqrt neg 14.644661
sub add 25 25 45 90 arc x -2 mul 25 sub 50 lineto x -2 mul 75 add -50
100 180 270 arc 25 0 150 270 315 arc x 2 mul 25 add 0 100 135 90 arcn x
2 mul 75 add 100 lineto x 2 mul 75 add -100 lineto 125 -50 50 270 180
arcn 75 0 lineto x 1250 sqrt neg 14.644661 add add -25 25 90 45 arcn x
1250 sqrt 14.644661 add add -25 25 225 270 arc x 2 mul 25 add -50 lineto
x 2 mul 75 sub 50 100 0 90 arc closepath gsave 0 setgray 100 3 div
setlinewidth stroke grestore 100 6 div setlinewidth stroke 0 .5 1
setrgbcolor/Q{x 150 moveto -25 0 150 90 135 arc x -2 mul 25 sub 0 100
315 270 arcn x -2 mul 75 sub -100 lineto x -2 mul 75 sub 100 lineto x
neg 1250 sqrt neg 14.644661 sub add 100 lineto stroke x neg 1250 sqrt
neg 14.644661 sub add neg -150 moveto x 2 mul 125 add -150 lineto x 2
mul 125 add 150 lineto x 2 mul 25 add 0 150 90 135 arc 25 0 100 315 270
arcn x neg -100 lineto stroke }def gsave Q 180 rotate Q grestore/B{x 100
sub 50 50 72 90 arc -45 0 rlineto stroke 212.132 3 div 318.198 3 div
moveto -60 -60 rmoveto -22 -22 rlineto stroke x 100 sub neg -50 100 198
222 arc stroke -73 0 moveto 1250 sqrt 10.355339 add neg -25 25 90 45
arcn 5 -5 rlineto stroke }def/C{x 100 sub 50 50 69 90 arc -48 0 rlineto
stroke x 100 sub neg -50 100 195 225 arc stroke 76 0 moveto 1250 sqrt
10.355339 add 25 25 270 225 arcn -7 7 rlineto stroke}def/E{212.132 3 div
318.198 3 div moveto -58 -58 rmoveto -26 -26 rlineto stroke}def gsave x
neg 25 sub 0 translate 0 setgray 100 3 div setlinewidth x neg 0 150 280
304.7 arc stroke x 0 100 117 135 arc -6 -6 rlineto stroke gsave B 180
rotate B grestore .16 .82 .16 setrgbcolor 100 6 div setlinewidth gsave C
180 rotate C grestore 0 .5 1 setrgbcolor x neg 0 150 278.5 305.8 arc
stroke x 0 100 115 137 arc -6 -6 rlineto stroke gsave E 180 rotate E
grestore grestore gsave x 25 add 0 translate 0 setgray 100 3 div
setlinewidth x 0 150 100 124.7 arc stroke x neg 0 100 297 315 arc 6 6
rlineto stroke gsave B 180 rotate B grestore .16 .82 .16 setrgbcolor 100
6 div setlinewidth gsave C 180 rotate C grestore 0 .5 1 setrgbcolor x 0
150 98.5 125.8 arc stroke x neg 0 100 295 317 arc 6 6 rlineto stroke
gsave E 180 rotate E grestore grestore showpage
%EOF

 

This vector image includes elements that have been taken or adapted from this file:

 12crossing-link-inrectangle.svg.