beginfig(151)
for i=0 step 1 until 360:
pair P;
P = 2cm* (sind(2*i), cosd(3*i));
fill fullcircle scaled 4mm shifted P withcolor white;
draw fullcircle scaled 4mm shifted P;
endfor;
picture p;
p:=nullpicture;
for i=-180 step 1 until 180:
pair P;
P = 2cm* (sind(2*i), cosd(3*i));
addto p contour fullcircle scaled 4mm shifted P withcolor white;
addto p doublepath fullcircle scaled 4mm shifted P
withpen pencircle scaled .5bp;
endfor;
clip p to (.5cm,2.5cm) -- (.5cm,1.5cm)--
(-.5cm,1.5cm) -- (-.5cm,2.5cm)--cycle;
draw p;
endfig;
end.