%% 
%%  The LaTeX Graphics Companion, 2ed (first printing May 2007)
%% 
%%  Example 7-4-13 on page 486.
%% 
%%  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{207.83385pt}
\StartShownPreambleCommands
\usepackage[matrix,arrow,frame]{xy}
\newcommand\topbar{\vrule height 0.4pt width 20mm}
\newcommand\previous{% turning-width of 15mm
  \save\ar`r[u]+/r15mm/`[u][u]\restore }
\newcommand\saved[2]{\txt{#1\\\emph{saved} $d[#2]$\\}}
\newcommand\bendto[2]{% creates a bendy arrow, offset 5mm
  \save c!C+/r5mm/\ar `r#1!C+/l#2/ `^r#1!C #1!C\restore}
\newcommand\dinput[1]{% label-offset 11mm
  \save +/l11mm/*{d[#1]}\restore}
\StopShownPreambleCommands
\begin{document}
\[\begin{xy}
\xymatrix"R" @M=0mm @H=12mm @W=20mm @R=0mm @*[F] {%
 {\txt{\topbar\\s\\\\ }}  %1,1
\\ \saved{A}{2}           %2,1
\\ \saved{B}{2}\previous  %3,1
\\ \saved{C}{3}           %4,1
}\turnradius{2mm}\POS(-30,+4)
\xymatrix @M=0mm @H=5mm @W=12mm @R=0mm @*[F] {%
   \dinput{1}\bendto{"R1,1"}{15mm}  %1,1
\\ \dinput{2}\bendto{"R3,1"}{17mm}  %2,1
\\ \dinput{3}\bendto{"R4,1"}{19mm}  %3,1
}
\end{xy}\]
\end{document}
