windingcheck:=0;
edges ee;
def overdraw expr c=ee:=nulledges;
 addto ee contour c; cull ee by (-1,1);
 cullit; addto currentpicture also -ee; cullit; draw c; enddef;
path p,q;
%q=fullcircle scaled 200 shifted 100right;
%q=((0,1)..(2,0)..(4,2)..(2,5.5)..(0,8)..(2,10)..(3.5,9)) scaled 20;
q=((43/2,9)..(43,-2)..(38,8)..
   (0,0)..(0,10)..(20,10)..(43,8)..(43,18)..(5,10)..(0,20)..cycle) scaled 6;
pickup pencircle scaled 3;
draw q; showit;
%for k=0 upto 35: overdraw fullcircle scaled 20 shifted point k/35*length q of q;
% showit; endfor
for k=1 upto 35: overdraw subpath((k-1)/35*length q,k/35*length q) of q--
  reverse subpath(-k/35*length q,-(k-1)/35*length q) of q--cycle; showit; endfor
shipit;
end