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 .7 def/phase 0 def aspiral
/sweeps .6 def/phase 36 def aspiral
/sweeps .8 def/phase 72 def aspiral
/sweeps .7 def/phase 108 def aspiral
/sweeps .6 def/phase 144 def aspiral
/sweeps .5 def/phase 180 def aspiral
/sweeps .7 def/phase 216 def aspiral
/sweeps .65 def/phase 252 def aspiral
/sweeps .5 def/phase 288 def aspiral
/sweeps .4 def/phase 324 def aspiral
grestore
%%%%%%%%%%%%%%%%
}def
/curvedge{gsave centerx centery translate rotf rotate
/lower 235.593 def/phase 324 def/incrm 16.52 def/sweeps .72 def aspiral
grestore/lower 0 def}def/extensions{
/lower 256.327 def/incrm 16.314 def/sweeps 300 360 div def/phase 144 def
 gsave centerx centery translate rotf rotate aspiral grestore
/lower 207.879 def/incrm 19.575 def/sweeps 268 360 div def/phase 180 def
 gsave centerx centery translate rotf rotate aspiral grestore
/lower 252 def/incrm 3.965 def/sweeps 256 360 div def/phase 0 def
 gsave centerx centery translate rotf rotate aspiral grestore
/lower 216 def/incrm 5.488 def/sweeps 223 360 div def/phase 36 def
 gsave centerx centery translate rotf rotate aspiral grestore
% /lower 340 def/incrm 6 def/sweeps 347 360 div def/phase 72 def
%  gsave centerx centery translate rotf rotate aspiral grestore
% /lower 299 def/incrm 8.5 def/sweeps 322 360 div def/phase 108 def
%  gsave centerx centery translate rotf rotate aspiral grestore
/lower 0 def/incrm 18 def}def/lower 0 def
/centerx 240 def/centery 306 def/rotf 0 def archimdouble curvedge extensions
/centerx 372 def/centery 306 def/rotf 72 def archimdouble curvedge extensions
/centerx 199.20975674250694001849726893187 def/centery 431.53946015096027151936999200597
def/rotf 288 def archimdouble curvedge extensions
/centerx 412.79024325749305998150273106813 def/centery 431.53946015096027151936999200597
def/rotf 144 def archimdouble curvedge extensions
/centerx 306 def/centery 509.12711345356672456963917801831 def/rotf 216 def archimdouble
curvedge extensions
306 396.841206751097453521675832406 translate
0 1 4{0 0 187.112 99 154.735 arc stroke
0 0 176.427 98.8 148.667 arc stroke pop 72 rotate}for
showpage
%EOF