Own work -- Converted from the following PostScript code:

%!
/archimdouble{
%%%%%%%%%%%%%%%%
% PostScript program to display an Archimedean spiral by approximating
% it with Bezier curves.  Displays a quintuple spiral (ten spirals
% rotated by 36 degree increments).
%%%  Parameters:
                 % centerx = horizontal coordinate of center of spiral
                 % centery = vertical coordinate of center of spiral
                 % rotf = degrees to rotate
/sepwid 110 def  % width separating successive turnings of spiral
                 % (a tenth of this between successive spirals)
/incrm 18 def    % insert a curve point after this number of degrees
%%%  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
        phase 324 eq phase 144 eq or{A 85 lt A 50 gt and{/flag flag neg def}if}if
        phase 288 eq phase 108 eq or{A 100 lt A 80 gt and{/flag flag neg def}if}if
        phase 252 eq phase 72 eq or{A 140 lt A 115 gt and{/flag flag neg def}if}if
        phase 216 eq phase 36 eq or{A 180 lt A 150 gt and{/flag flag neg def}if}if
        phase 216 eq phase 36 eq or{A 30 lt A 15 gt and{/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 pi
            div def
        /nextdist x nextx sub dup mul y nexty sub dup mul add sqrt pi
            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
/sweeps .9 def/phase 0 def aspiral
/sweeps .8 def/phase 36 def aspiral
/sweeps .8 def/phase 72 def aspiral
/sweeps .7 def/phase 108 def aspiral
/sweeps .9 def/phase 144 def aspiral
/sweeps .8 def/phase 180 def aspiral
/sweeps 1.051 def/phase 216 def aspiral
/sweeps .95 def/phase 252 def aspiral
/sweeps .85 def/phase 288 def aspiral
/sweeps .75 def/phase 324 def aspiral
grestore
%%%%%%%%%%%%%%%%
}def
-5 0 translate
/curvedge{gsave centerx centery translate rotf rotate
/lower 307.58 def/phase 180 def/incrm 8.745 def/sweeps .9 def aspiral
/lower 375.825 def/incrm 13.897 def/sweeps 1.1 def aspiral
grestore/lower 0 def}def/extensions{
/lower 288 def/incrm 16.19 def/sweeps 310 360 div def/phase 36 def
 gsave centerx centery translate rotf rotate aspiral grestore
/lower 324 def/incrm 9.238 def/sweeps 334 360 div def/phase 0 def
 gsave centerx centery translate rotf rotate aspiral grestore
/lower 378 def/incrm 11 def/sweeps 395 360 div def/phase 216 def
 gsave centerx centery translate rotf rotate aspiral grestore
/lower 342 def/incrm 13 def/sweeps 359 360 div def/phase 252 def
 gsave centerx centery translate rotf rotate aspiral grestore
/lower 306 def/incrm 12 def/sweeps 323 360 div def/phase 288 def
 gsave centerx centery translate rotf rotate aspiral grestore
/lower 270 def/incrm 14 def/sweeps 289 360 div def/phase 324 def
 gsave centerx centery translate rotf rotate aspiral grestore
/lower 0 def/incrm 18 def}def/lower 0 def
/centerx 218 def/centery 276 def/rotf 0 def archimdouble curvedge extensions
/centerx 394 def/centery 276 def/rotf 72 def archimdouble curvedge extensions
/centerx 163.61300899000925335799635857583 def/centery 443.38594686794702869249332267472
def/rotf 288 def archimdouble curvedge extensions
/centerx 448.38699100999074664200364142417 def/centery 443.38594686794702869249332267472
def/rotf 144 def archimdouble curvedge extensions
/centerx 306 def/centery 546.83615127142229942618557069118 def/rotf 216 def archimdouble
curvedge extensions
306 397.12160900146327136223444320816 translate
/quint1{/phase 36 def aspiral/phase 108 def aspiral/phase 180 def aspiral
 /phase 252 def aspiral/phase 324 def aspiral}def
/quint2{/phase 0 def aspiral/phase 72 def aspiral/phase 144 def aspiral
 /phase 216 def aspiral/phase 288 def aspiral}def
gsave 11.89 rotate/sweeps 2.80 def/lower 875 def quint2 grestore
gsave 11.7 rotate/sweeps 2.72 def/lower 839.8 def quint1 grestore
gsave 10.95 rotate/sweeps 2.39 def/lower 803.8 def quint2
 /incrm 1.257 def/lower 857.8 def/sweeps 2.39 def quint2 grestore/incrm 18 def
gsave 10.45 rotate/sweeps 2.285 def/lower 768.7 def quint1
 /incrm 7.188 def/lower 804.7 def/sweeps 2.285 def quint1 grestore
showpage
%EOF