% --- start of displayed preamble in the book ---
input metauml
% --- end of displayed preamble in the book ---
defaultfont:="ptmr8r";
warningcheck:=0;
beginfig(1)
Class.A("A")()();
Class.B("B")()();
B.sw=A.ne+(30,10);
drawObjects(A,B);
z=A.se + (30,-10);
link(transition)
    (pathCut(A,B)(A.c--z--B.c));
endfig;
end;