%% 
%%  A DANTE-Edition example
%% 
%%  Example 16-04-25 on page 251.
%% 
%%  Copyright (C) 2011 Herbert Voss
%% 
%%  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.
%% 
%% 
%% ==== 
% Show page(s) 1
%% 
\documentclass[]{article}
\pagestyle{empty}
\setlength\textwidth{177.70511pt}
\setlength\parindent{0pt}

\usepackage{pstricks,pst-node}

\begin{document}
\begin{pspicture}(3,3)\large\bfseries
  \psset{nodesep=3pt,linearc=0.3}
  \rput[bl](0,0){\rnode{A}{1}}
  \rput[tr](3,3){\rnode{B}{2}}
  \ncbox{A}{B}\rput[lt](0,3){\rnode{A}{3}}
  \rput[rb](3,0){\rnode{B}{4}}
  \ncbox*[border=4pt,
    linecolor=lightgray]{->}{A}{B}
  \rput[lt](0,3){\rnode{A}{3}}
  \rput[rb](3,0){\rnode{B}{4}}
\end{pspicture}
\end{document}