%% 
%%  The LaTeX Graphics Companion, 2ed (first printing May 2007)
%% 
%%  Example 7-4-1 on page 479.
%% 
%%  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{135.83385pt}
\StartShownPreambleCommands
\usepackage[arrow]{xy}
\StopShownPreambleCommands
\begin{document}
\[\begin{xy}
  (0,-20)="a", (0,0)="b"
  \ar@{<.||}  @<24mm>  "a";"b" \ar@^{<.||} @<16mm>  "a";"b"
  \ar@_{<.||} @<8mm>   "a";"b" \ar@0{<.||}          "a";"b"
  \ar@1{<.||} @<-8mm>  "a";"b" \ar@2{<.||} @<-16mm> "a";"b"
  \ar@3{<.||} @<-24mm> "a";"b"
  \end{xy}\]
\end{document}
