The overall basic structure of the windings is partially based on a small JPEG image at the http://www.labyrinthos.net/ site, but the geometry and graphic realization is entirely different.

Self-made graphic, created by combining the output of the following two snippets of vector PostScript source code:

%!
300 396 translate 1 setlinecap 1 setlinejoin 10 setlinewidth
/turn1 250.52877936551 def/turn2 -66.4218215218 def -1 1 scale
0 -60 moveto 100 turn2 cos mul 100 turn2 sin mul 40 180 turn2
arc 0 0 140 turn2 turn1 arc
120 turn1 cos mul 120 turn1 sin mul 20 turn1 turn1 180 add arc
0 0 100 turn1 turn2 arcn stroke 0 0 120 turn1 turn2 arcn
100 turn2 cos mul 100 turn2 sin mul 20 turn2 turn2 180 sub arcn
0 0 80 turn2 180 arc -80 -33.137 -44.1826 -60 0 -60 curveto
0 0 60 -90 180 arc -60 -22.0913 -33.137 -40 0 -40 curveto
0 0 40 -90 180 arc -40 -11.0457 -22.0913 -20 0 -20 curveto
0 0 20 -90 180 arc -13.3333 0 -6.6667 0 0 0 curveto stroke
showpage
%EOF

%!
/archim{
%%%%%%%%%%%%%%%%
% PostScript program to display an Archimedean spiral by approximating
% it with Bezier curves.
%%%  Parameters:
                 % centerx = horizontal coordinate of center of spiral
                 % centery = vertical coordinate of center of spiral
                 % rotf = degrees to rotate
/sepwid 20 def   % width separating successive turnings of spiral
                 % incrm = insert a curve point every these degrees
/sweeps swp2 def % number of 360 degree turnings to show
                 % double - 0 to display single spiral, else double
%%%  Procedures:
/pi 3.1415926535898 def/radians 57.295779513082 def
/sepwid sepwid pi div 2 div def
gsave centerx centery translate rotf rotate
/aspiral{/first 1 def
    lower incrm sweeps 360 mul{8{dup}repeat
        phase add cos/costh exch def
        phase add sin/sinth exch def
        costh mul radians div/thcosth exch def
        sinth mul radians div/thsinth exch def
        thcosth sepwid mul/x exch def
        thsinth sepwid mul/y exch def
        0 eq phase 90 eq phase 270 eq or and{/slope 999999999 def}{/slope
        sinth thcosth add costh thsinth sub div def}ifelse
        sinth 0 gt sinth 0 eq costh -1 eq and or{/flag -1 def}{/flag 1
            def}ifelse
        /A exch def phase 0 eq phase 180 eq or {A 49.29348 lt A 180 gt A
            196.273450852 lt and A 360 gt A 368.8301 lt and A 540 gt A
            545.9907 lt and A 720 gt A 724.5217 lt and A 900 gt A
            903.6281968 lt and or or or or or{/flag flag neg def}if}if
            phase 120 eq phase 300 eq or{A 10 lt A 80 gt A 100 lt and
            or{/flag flag neg def}if}if
        incrm sub 3{dup}repeat phase add cos sepwid mul mul radians div
            /prevx exch def phase add sin sepwid mul mul radians div
            /prevy exch def
        incrm add 3{dup}repeat phase add cos sepwid mul mul radians div
            /nextx exch def phase add sin sepwid mul mul radians div
            /nexty exch def
        /prevdist x prevx sub dup mul y prevy sub dup mul add sqrt 2.55
            div def
        /nextdist x nextx sub dup mul y nexty sub dup mul add sqrt 2.55
            div def
        /normaliz slope slope mul 1 add sqrt def
        0 eq{0 0 moveto/prevbezx phase cos nextdist mul def/prevbezy
            phase sin nextdist mul def/first 0 def}{first 1 eq{x y
            moveto/first 0 def}{prevbezx prevbezy x 1 flag mul
            normaliz div prevdist mul sub y slope flag mul normaliz
            div prevdist mul sub x y curveto}ifelse
        /prevbezx x 1 flag mul normaliz div nextdist mul add def
        /prevbezy y slope flag mul normaliz div nextdist mul add def}ifelse}
    for stroke}def
/phase 0 def aspiral grestore}def
300 396 translate 10 setlinewidth 1 setlinecap 1 -1 scale
/centerx 0 def/centery 0 def/rotf 0 def
/lower 105 def/swp2 4.17 def/incrm 15 def archim
/lower 1500 def/swp2 4.19 def/incrm 7.3203 def archim
40 95.7183 20 -112.6797047102 67.3202952898 arcn stroke
/lower 2220 def/swp2 6.19 def/incrm 7.3203 def archim
/lower 1920 def/swp2 6.17 def/incrm 15 def archim
/lower 1912.1199 def/swp2 5.34 def/incrm 7.8801 def archim
/lower 1552.1199 def/swp2 4.34 def/incrm 7.8801 def archim
/lower 1560 def/swp2 5.17 def/incrm 15 def archim
/lower 1860 def/swp2 5.19 def/incrm 7.3203 def archim
-40 98.4102 20 -67.880129774128021 112.1198702259 arc stroke
/lower 2272.1199 def/swp2 6.34 def/incrm 7.8801 def archim
/lower 2280 def/swp2 7.17 def/incrm 15 def archim
/lower 2580 def/swp2 7.19 def/incrm 7.3203 def archim
40 95.7183 40  67.3202952898 180 arc 0 65 lineto stroke
showpage
%EOF