%% 
%%  The LaTeX Graphics Companion, 2ed (first printing May 2007)
%% 
%%  Example 6-2-31 on page 348.
%% 
%%  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}  \SpecialCoor
\StopShownPreambleCommands
\begin{document}
\begin{pspicture}(3,3)
  \rput[bl](0,0){\ovalnode{A}{Idea 1}}
  \rput[tr](3,3){\ovalnode{B}{Idea 2}}
  \pcdiag[angleA=90,angleB=-90,arm=1.25cm]{->}(A)(B)
  \rput[lt](0,3){\rnode{A}{Idea 3}}
  \rput[rb](3,0){\rnode{B}{Idea 4}}
  \pcdiag[angleA=-90,angleB=90,arm=0]{->}(A)(B)
\end{pspicture}
\end{document}