%% 
%%  A DANTE-Edition example
%% 
%%  Example 16-10-1 on page 264.
%% 
%%  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{375.57637pt}
\setlength\parindent{0pt}

\usepackage{pstricks,pst-node}
\def\ncIII#1#2#3#4#5#6#7{
  \ncline[linecolor=#5,linewidth=2pt]{#1}{#2}
  \ncline[linecolor=magenta,offset=2mm,arrows=<-,nodesepA=4mm]{#1}{#2}
  \ncline[linecolor=magenta,offset=-2mm,arrows=->]{#1}{#2}
  \ncline[linecolor=#6,linewidth=2pt]{#1}{#3}
  \ncline[linecolor=magenta,offset=2mm,arrows=<-,nodesepA=4mm]{#1}{#3}
  \ncline[linecolor=magenta,offset=-2mm,arrows=->,nodesepA=4mm]{#1}{#3}
  \ncline[linecolor=#7,linewidth=2pt]{#1}{#4}
  \ncline[linecolor=magenta,offset=2mm,arrows=<-]{#1}{#4}
  \ncline[linecolor=magenta,offset=-2mm,arrows=->,nodesepA=4mm]{#1}{#4}}

\begin{document}
\psset{fillstyle=solid,fillcolor=black!30}
\begin{psmatrix}[colsep=0.75cm]
& & & & & [name=a]\psframebox{\textcolor{red}{\textbf{7}}} \\
& [name=b]\pscirclebox{7} & & & & [name=c]\pscirclebox{4} & & & &
                                    [name=d]\pscirclebox{1}\\[0pt]
[name=e]\psframebox{9} & [name=f]\psframebox{8} & [name=g]\psframebox{7} & &
[name=h]\psframebox{6} & [name=i]\psframebox{5} & [name=j]\psframebox{4} & &
[name=k]\psframebox{6} & [name=l]\psframebox{5} & [name=m]\psframebox{4}
\end{psmatrix}
\ncIII{a}{b}{c}{d}{cyan}{black}{black}
\ncIII{b}{e}{f}{g}{cyan}{black}{black}
\ncIII{c}{h}{i}{j}{black}{black}{black}
\ncIII{d}{k}{l}{m}{black}{black}{black}
\end{document}
