tracingstats:=1;
%prologues:=2;
texlabels := 1;
u:=10bp;
input mpcirc;

beginfig(9)
wd:=4u;
n:=3;

prepare (V,whatI);
for i=1 upto n:
  prepare (R[i], L[i], C[i]);
  z[i] = wd*up rotated (if i > 2: (360/n) else: 120 fi * (i-1));
  z[i+n] = 3 * z[i];
endfor;


for i=1 upto n:
  j := i mod n + 1;
  betw(C[i]) j,i;
  betw(L[i]) i,i+n;
  if i=1:
    z.a=.5[z[n+1],z[n+2]];
    betw(R1) z.a,n+1;
    betw(V) n+2,z.a;
  else:
    betw(R[i]) n+j,n+i;
    if i = n:
      betw(whatI) n+1,R[n]a;
    fi;
  fi;
endfor;


edraw;
junction 1,2,3,4,5,6;

endfig;

end