numeric d;
numeric ratiox, ratioy;

def mycircle(expr x, y)=
draw (x-d,y)..(x,y+d)..(x+d,y)..(x,y-d)..cycle
enddef;

def myline(expr x, y, z, w) =
save ratioy, ratiox;
ratiox:=(z-x)/(sqrt((z-x)*(z-x)+(w-y)*(w-y)));
ratioy:=(w-y)/(sqrt((z-x)*(z-x)+(w-y)*(w-y)));
draw (x+d*ratiox,y+d*ratioy)--(z-d*ratiox,w-d*ratioy);
enddef;

def mybline(expr x, y, z, w) =
save ratioy, ratiox;
pickup pencircle scaled 1.5pt;
ratiox:=(z-x)/(sqrt((z-x)*(z-x)+(w-y)*(w-y)));
ratioy:=(w-y)/(sqrt((z-x)*(z-x)+(w-y)*(w-y)));
draw (x+d*ratiox,y+d*ratioy)--(z-d*ratiox,w-d*ratioy);
pickup pencircle scaled .5pt;
enddef;


beginfig(1);
numeric x[],y[];
u:=1.3cm;
d:=0.05u;


for i=0 upto 4:
  x[i]:=u*cosd(72*i+18); y[i]:=u*sind(72*i+18);
  mycircle(x[i],y[i]);
endfor
  myline(x[0],y[0],x[1],y[1]);
  myline(x[0],y[0],x[2],y[2]);
  myline(x[0],y[0],x[3],y[3]);
  myline(x[0],y[0],x[4],y[4]);
  myline(x[1],y[1],x[2],y[2]);
  myline(x[1],y[1],x[3],y[3]);
  myline(x[1],y[1],x[4],y[4]);
  myline(x[2],y[2],x[3],y[3]);
  myline(x[2],y[2],x[4],y[4]);
  myline(x[3],y[3],x[4],y[4]);
endfig;

beginfig(2);
u:=1.3cm;
d:=0.05u;
numeric x[],y[];
l:=-u/2;
r:=u/2;
h:=u;
x[0]:=l; y[0]:=-h/2;
x[1]:=l; y[1]:=h/2;
x[2]:=r; y[2]:=0;
x[3]:=r; y[3]:=-h;
x[4]:=r; y[4]:=h;
for i=0 upto 4:
  mycircle(x[i],y[i]);
endfor
for i=2 upto 4:
  myline(x[0],y[0],x[i],y[i]);
  myline(x[1],y[1],x[i],y[i]);
endfor
endfig;

beginfig(3);
numeric a;
u:=1.3cm;
d:=0.05u;
for i=0 upto 4:
  y[i]:=0;
  x[i]:=i*u/2;
  mycircle(x[i],y[i]);
endfor;
for i=0 upto 3:
  myline(x[i],y[i],x[i+1],y[i+1]);
endfor;

endfig;

beginfig(4);
numeric x[],y[];
u:=1.3cm;
d:=0.05u;

for i=0 upto 4:
  x[i]:=u*cosd(72*i+18); y[i]:=u*sind(72*i+18);
  mycircle(x[i],y[i]);
endfor
for i=0 upto 4:
  myline(x[i],y[i],x[(i+1)mod5],y[(i+1)mod5]);
  %myline(x[i],y[i],x[i+1],y[i+1]);
endfor
endfig;

beginfig(5);
numeric x[],y[];
u:=1.3cm;
d:=0.05u;

for i=0 upto 3:
  x[i]:=i*u; y[i]:=i*u;
endfor

x5:=(x1+x2)/2;

mycircle (x1,y1);
mycircle (x1,y2);
mycircle (x2,y1);
mycircle (x2,y2);
mycircle (x0,y2);
mycircle (x3,y2);

myline (x1,y1,x2,y1);
%myline (x2,y2,x2,y1);
%myline (x1,y1,x1,y2);
myline (x2,y2,x1,y2);
myline (x1,y2,x0,y2);
myline (x3,y2,x2,y2);
myline (x1,y1,x0,y2);
myline (x3,y2,x2,y1);
myline (x1,y1,x2,y2);

myline (x0,y2,x0,y3);
myline (x1,y2,x1,y3);
myline (x2,y2,x2,y3);
myline (x3,y2,x3,y3);
draw (x0,y3-d)--(x3,y3-d);

myline (x1,y2,x5,y3);
myline (x2,y1,x5,y0);
myline (x0,y2,x0,y0);
myline (x3,y2,x3,y0);
draw (x0,y0+d)--(x3,y0+d);
myline (x1,y1,x1,y0);
myline (x2,y1,x2,y0);
myline (x1,y1,x0-d,y1);
myline (x2,y1,x3+d,y1);


endfig;

\end