<html><head><meta name="color-scheme" content="light dark"></head><body><pre style="word-wrap: break-word; white-space: pre-wrap;">%% 
%%  The LaTeX Graphics Companion, 2ed (first printing May 2007)
%% 
%%  Example 7-4-35 on page 503.
%% 
%%  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[all,web]{xy}\usepackage{ifthen}
\StopShownPreambleCommands
\begin{document}
\[\renewcommand{\latticebody}{%
  \ifthenelse{\latticeA=1}{%
    \ifthenelse{\latticeB=1}{\drop{\dir{*}}}%
                            {\drop{\dir{o}}}}%
    {\drop{\dir{x}}}}
\begin{xy}
 *\xybox{0;&lt;8mm,4mm&gt;:&lt;4mm,8mm&gt;::
 ,0,{\croplattice{-6}{6}{-6}{6}%
                 {-3}{3}{-3.5}{3.5}}%
     }="S"
 ,{"S"+L \ar "S"+R*+!L{z_1}}
 ,{"S"+D \ar "S"+U*+!D{z_2}}
\end{xy}\]
\end{document}
</pre></body></html>