%% 
%%  The LaTeX Graphics Companion, 2ed (first printing May 2007)
%% 
%%  Example 6-2-37 on page 351.
%% 
%%  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{pstricks,pst-node}
\StopShownPreambleCommands
\begin{document}
\begin{pspicture}(2,2)\psgrid[subgriddiv=2]
  \cnode(0.25,1.75){0.25cm}{A} \cnode(1.75,0.25){0.25cm}{B}
  \cnode(1.75,1.75){0.25cm}{C} \cnode(0.25,0.25){0.25cm}{D}
  \ncline[nodesep=0.25]{<->}{A}{B}
  \ncline[Ynodesep=0.25]{<->}{C}{D}
\end{pspicture}
\end{document}
