%% 
%%  The LaTeX Graphics Companion, 2ed (first printing May 2007)
%% 
%%  Example 7-3-1 on page 475.
%% 
%%  Copyright (C) 2007 Michel Goossens, Frank Mittelbach, Denis Roegel, Sebastian Rahtz, Herbert Vo\ss 
%% 
%%  It may be distributed and/or modified under the conditions
%%  of the LaTeX Project Public License, either version 1.3
%%  of this license or (at your option) any later version.
%% 
%%  See http://www.latex-project.org/lppl.txt for details.
%% 

\documentclass{ttctexa}
\pagestyle{empty}
\setcounter{page}{6}
\setlength\textwidth{183.83385pt}
\StartShownPreambleCommands
\usepackage[curve,frame]{xy}
\StopShownPreambleCommands
\begin{document}
\[\begin{xy}
  0*[o]+{L};(50,20)*[o]+{R}="R"
        **\crv{} ?(.6)*@{+}*^+!UL{0}
   ,"R" **\crv{(30,30)} ?*@{+}*^+!DR{1}
   ,"R" **\crv{(20,30)&(30,40)} ?*@{+}*^+!DR{2}
   ,"R" **\crv{(10,-20)&(25,-20)&(40,20)}
     ?(.4)*@{+}*^+!DR{3}
   ,"R" **\crv{(0,-10)&(12,-20)&(28,25)&(40,20)}
     ?(.4)*@{+}*^+!DR{4}
 \end{xy}\]

\end{document}