u=1cm;
r=3pt;

beginfig(1);
z0=(0,0);
z1=z0+u*dir150;
z2=z0+u*dir30;
z3=z0+u*dir-30;
z4=z0+u*dir-150;
draw z0--z1--z4--z0--z2--z3--z0;
pickup pencircle scaled 2r;
for i=0 upto 4:  draw z[i];  endfor
label.ulft(btex$a$etex, z1+r*dir150);
label.urt(btex$b$etex, z2+r*dir30);
label.top(btex$c$etex, z0+r*dir90);
label.llft(btex$d$etex, z4+r*dir-150);
label.lrt(btex$e$etex, z3+r*dir-30);
endfig;

beginfig(2);
for i=0 upto 4:  z[i] = u*dir(-360/5*i+90);  endfor
z[5]=(0,-u/4);
draw z0--z1--z2--z3--z4--z0;
draw z4--z1--z5--z3;
draw z0--z5--z2;
draw z0..z4+u*dir-135..z3;
pickup pencircle scaled 2r;
for i=0 upto 5:  draw z[i];  endfor
label.urt(btex$a$etex, z0+r*dir45);
label.urt(btex$c$etex, z1+r*dir45);
label.lrt(btex$f$etex, z2+r*dir-45);
label.bot(btex$e$etex, z3+r*dir-90);
label.ulft(btex$b$etex, z4+r*dir-135);
label.ulft(btex$d$etex, z5+r*dir-135);
endfig;

beginfig(3);
for i=0 upto 4:  z[i] = u*dir(-360/5*i+90);  endfor
for i=0 upto 3:  for j=i upto 4:  draw z[i]--z[j];  endfor;  endfor
pickup pencircle scaled 2r;
for i=0 upto 4:  draw z[i];  endfor
label.top(btex$a$etex, z[0]+r*dir90);
label.rt(btex$b$etex, z[1]+r*dir0);
label.lrt(btex$c$etex, z[2]+r*dir-45);
label.llft(btex$d$etex, z[3]+r*dir-135);
label.lft(btex$e$etex, z[4]+r*dir180);
endfig;

beginfig(4);
z0=(0,0);
z1=2u*dir90;
z2=2u*dir-30;
z3=2u*dir-150;
z4=2u/3*dir30;
z5=2u/3*dir150;
z6=2u/3*dir-90;
draw z0--z4--z1--z0--z5--z3--z0--z6--z2--z0;
draw z1--z2--z3--z1;
pickup pencircle scaled 2r;
for i=0 upto 6:  draw z[i];  endfor
label.ulft(btex$d$etex, z0+r*dir90);
label.top(btex$a$etex, z1+r*dir90);
label.lrt(btex$g$etex, z2+r*dir-45);
label.llft(btex$f$etex, z3+r*dir-135);
label.bot(btex$c$etex, z4+r*dir-90);
label.top(btex$b$etex, z5+r*dir90);
label.lft(btex$e$etex, z6+r*dir180);
endfig;

beginfig(5);
z0=(0,0);
z1=z0+u*dir120;
z2=z1+u*dir60;
z3=z1+u*dir180;
z4=z0+u*dir-120;
z5=z4+u*dir180;
z6=z4+u*dir-60;
z7=z0+3u/2*dir0;
z8=z9+u*dir0;
z9=z7+u*dir60;
z10=z7+u*dir-60;
z11=z10+u*dir0;
z12=z10+u*dir-120;
draw z0--z1--z2;
draw z1--z3;
draw z0--z4--z5;
draw z4--z6;
draw z0--z7--z9--z8;
draw z7--z10--z11;
draw z10--z12;
pickup pencircle scaled 2r;
for i=0 upto 12:  draw z[i];  endfor
label.urt(btex$a$etex, z2+r*dir45);
label.lft(btex$b$etex, z3+r*dir180);
label.rt(btex$c$etex, z1+r*dir0);
label.lft(btex$d$etex, z0+r*dir180);
label.rt(btex$e$etex, z4+4*dir0);
label.lft(btex$f$etex, z5+r*dir180);
label.bot(btex$g$etex, z6+r*dir-90);
label.rt(btex$h$etex, z8+r*dir0);
label.ulft(btex$i$etex, z9+r*dir135);
label.rt(btex$j$etex, z7+r*dir0);
label.rt(btex$k$etex, z11+r*dir0);
label.lft(btex$l$etex, z10+r*dir180);
label.bot(btex$m$etex, z12+r*dir-90);
endfig;

beginfig(6);
z0=(0,0);
z1=z0+2u*dir45;
z2=z0+2u*dir-45;
z3=z1+2u*dir-45;
z4=z3+2u*dir45;
z5=z3+2u*dir-45;
z6=z4+2u*dir-45;
draw z0--z1--z4--z3--z5--z2--z0;
draw z1--z2;
draw z0--z3--z6;
pickup pencircle scaled 2r;
for i=0 upto 6:  draw z[i];  endfor
label.lft(btex$a$etex, z0+r*dir180);
label.ulft(btex$b$etex, z1+r*dir135);
label.llft(btex$c$etex, z2+r*dir-135);
label.ulft(btex$d$etex, z3+r*dir135);
label.urt(btex$e$etex, z4+r*dir45);
label.lrt(btex$f$etex, z5+r*dir-45);
label.rt(btex$g$etex, z6+r*dir0);
endfig;

end;