%def overdraw expr c = erase fill c; draw c enddef;
def overdraw expr c = begingroup picture temp; temp:=nullpicture;
 interim turningcheck:=0; addto temp contour c; cull temp excluding (0,0);
 cullit; addto currentpicture also -temp; cullit; draw c endgroup enddef;
forsuffixes m=1.5,3,5,10:
def link(expr n) = overdraw subpath 1/m(n,n+1) of M --
		subpath 1/m(n+1+8*m,n+8*m) of M -- cycle enddef;


beginchar(0,0,0,0); decimal m & " subdivisions per knot";
z1=(20,-13); z2=(30,-6); z3=(20,1); z4=(4,-7);
 z5=(-12,-13); z6=(-24,-4); z7=(-15,6);
path M; M=(origin..z1..z2..z3..z4..z5..z6..z7..
	    origin..-z7..-z6..-z5..-z4..-z3..-z2..-z1..cycle) scaled 6
shifted 150right;
pickup pencircle scaled 3;
for k=1 upto 4*m: link(k+4*m-1); link(4*m-k); showit; endfor
endchar;
endfor