%% 
%%  Ein Beispiel der DANTE-Edition
%%  
%%  7. Auflage
%% 
%%  Beispiel 32-03-62 auf Seite 760.
%% 
%%  Copyright (C) 2016 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
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\documentclass[]{exaarticle}
\pagestyle{empty}
\setlength\textwidth{193.16928pt}
\setlength\parindent{0pt}
%StartShownPreambleCommands
\usepackage{pst-electricfield}
%StopShownPreambleCommands
\begin{document}
\begin{pspicture*}(-6,-6)(6,6)
  \psgrid[subgriddiv=0,gridcolor=gray,griddots=10]
  \psElectricfield[Q={[-1 -2 2][1 2 2][-1 2 -2][1 -2 -2]},linecolor=red]
  \psEquipotential[Q={[-1 -2 2][1 2 2][-1 2 -2][1 -2 -2]},
    linecolor=blue](-6.1,-6.1)(6.1,6.1)
  \psEquipotential[Q={[-1 -2 2][1 2 2][-1 2 -2][1 -2 -2]},linecolor=green,
    linewidth=2\pslinewidth,Vmax=0,Vmin=0](-6.1,-6.1)(6.1,6.1)
\end{pspicture*}
\end{document}
