% --- start of displayed preamble in the book ---
input metaobj
% Circles produced as before

% --- end of displayed preamble in the book ---

  newCircle.a(btex start etex);
  newCircle.b(btex end etex);
  a.c=origin;
  b.c-a.c=(3cm,1cm);

defaultfont:="ptmr8r";
warningcheck:=0;
beginfig(1)
ncdiag(a)(b) "angleA(90)", "angleB(50)",
  "linecolor(blue)","linewidth(1pt)",
  "armA(3cm)","armB(2cm)";
drawObj(a,b);
endfig;
end;