u := 2.2cm;
r := 0.35cm;

ahlength:=0.2cm;  % arrowhead length
def arrow(expr a, b)=drawarrow a+r*dir angle(b-a)--b+r*dir angle(a-b); enddef;

beginfig(1);
z1=(0,0);
z2=z1+u*dir-90;
z3=z1+1.6u*dir0;
z2-z1=z4-z3=z5-z4=z7-z6=z8-z7=z10-z9;
z3-z1=z6-z3=z4-z2=z7-z4=z8-z5;
x9-x6=x6-x3;
y9=(y6+y7)/2;
for i=1 upto 10:
	draw  for theta=0 step 10 until 350:  z[i]+r*dir theta..  endfor  cycle;
endfor
arrow(z2,z3);
arrow(z2,z4);
arrow(z2,z5);
arrow(z3,z6);
arrow(z3,z7);
arrow(z4,z7);
arrow(z4,z8);
arrow(z5,z7);
arrow(z5,z8);
arrow(z6,z9);
arrow(z7,z9);
arrow(z7,z10);
arrow(z8,z10);
label("21", z1);
label("5", z2);
label("4", z3);
label("10", z4);
label("6", z5);
label("7", z6);
label("3", z7);
label("4", z8);
label("8", z9);
label("6", z10);
label.top(btex$T_1$etex, z1+r*dir90);
label.top(btex$T_2$etex, z2+r*dir90);
label.top(btex$T_3$etex, z3+r*dir90);
label.top(btex$T_4$etex, z4+r*dir90);
label.top(btex$T_5$etex, z5+r*dir90);
label.top(btex$T_6$etex, z6+r*dir90);
label.top(btex$T_7$etex, z7+r*dir90);
label.top(btex$T_8$etex, z8+r*dir90);
label.top(btex$T_9$etex, z9+r*dir90);
label.top(btex$T_{10}$etex, z10+r*dir90);
endfig;

beginfig(2);
z1=(0,0);
z2=z1+u*dir-90;
x3=x1+1.6u;
y1=(y3+y4)/2;
z2-z1=z4-z3=z5-z4=z7-z6=z10-z9;
x3-x1=x6-x3=x9-x6;
y3=y6=y9;
y8-y7=y7-y6;
x8=(x7+x10)/2;
for i=1 upto 10:
	draw  for theta=0 step 10 until 350:  z[i]+r*dir theta..  endfor  cycle;
endfor
arrow(z1,z3);
arrow(z1,z4);
arrow(z1,z5);
arrow(z2,z4);
arrow(z2,z5);
arrow(z3,z6);
arrow(z3,z7);
arrow(z4,z7);
arrow(z4,z8);
arrow(z5,z8);
arrow(z6,z10);
arrow(z7,z10);
arrow(z7,z8);
arrow(z8,z10);
label("5", z1);
label("1", z2);
label("10", z3);
label("6", z4);
label("20", z5);
label("3", z6);
label("7", z7);
label("4", z8);
label("25", z9);
label("5", z10);
label.top(btex$T_1$etex, z1+r*dir90);
label.top(btex$T_2$etex, z2+r*dir90);
label.top(btex$T_3$etex, z3+r*dir90);
label.top(btex$T_4$etex, z4+r*dir90);
label.top(btex$T_5$etex, z5+r*dir90);
label.top(btex$T_6$etex, z6+r*dir90);
label.top(btex$T_7$etex, z7+r*dir90);
label.rt(btex$T_8$etex, z8+r*dir0);
label.top(btex$T_9$etex, z9+r*dir90);
label.top(btex$T_{10}$etex, z10+r*dir90);
endfig;

beginfig(3);
z1=(0,0);
z2=z1+u*dir-90;
z3=z1+1.2u*dir0;
z4=z3+u*dir-90;
z5-z4=z4-z2;
z6=z5+1.3u*dir40;
for i=1 upto 6:
	draw  for theta=0 step 10 until 350:  z[i]+r*dir theta..  endfor  cycle;
endfor
arrow(z1,z3);
arrow(z1,z4);
arrow(z2,z4);
arrow(z3,z5);
arrow(z4,z5);
arrow(z6,z5);
label("4", z1);
label("5", z2);
label("8", z3);
label("4", z4);
label("6", z5);
label("7", z6);
label.top(btex$T_1$etex, z1+r*dir90);
label.top(btex$T_2$etex, z2+r*dir90);
label.top(btex$T_3$etex, z3+r*dir90);
label.top(btex$T_4$etex, z4+r*dir90);
label.top(btex$T_5$etex, z5+r*dir90);
label.top(btex$T_6$etex, z6+r*dir90);
endfig;

beginfig(4);
z1=(0,0);
z2=z1+u*dir-90;
z3=z1+u*dir0;
y4-y3=y2-y1;
x4=(x3+x5)/2;
z5=z3+u*dir0;
x6=x5+u;
y6=(y4+y5)/2;
for i=1 upto 6:
	draw  for theta=0 step 10 until 350:  z[i]+r*dir theta..  endfor  cycle;
endfor
arrow(z1,z3);
arrow(z1,z4);
arrow(z2,z4);
arrow(z3,z5);
arrow(z4,z6);
arrow(z5,z6);
label("8", z1);
label("3", z2);
label("2", z3);
label("7", z4);
label("9", z5);
label("5", z6);
label.top(btex$T_1$etex, z1+r*dir90);
label.top(btex$T_2$etex, z2+r*dir90);
label.top(btex$T_3$etex, z3+r*dir90);
label.top(btex$T_4$etex, z4+r*dir90);
label.top(btex$T_5$etex, z5+r*dir90);
label.top(btex$T_6$etex, z6+r*dir90);
endfig;

bye