%% 
%%  Ein Beispiel der DANTE-Edition
%%  
%%  7. Auflage
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%%  Beispiel 32-03-17 auf Seite 733.
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%%  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-optic}
%StopShownPreambleCommands
\begin{document}
\begin{pspicture}(-8,-2)(8,5.75)
\pnode(-8,1.5){A}\pnode(8,1.5){B}\uput[45](A){A}\uput[135](B){B}\pnode(0,0){START}
\psframe[fillcolor=lightgray,fillstyle=solid,linecolor=blue](-8,-1.5)(B)
\psset{linecolor=red,arrowsize=3pt,arrows=->}
\multido{\n=20+5}{29}{%
  \refractionRay(START)(1;\n)(A)(B){1.5}{1}{END}
  \arrowLine(START)(END){2}\arrowLine(END)(END'){1}
  \psOutLine[length=3](END)(END'){Q}\arrowLine(END')(Q){3} }
\end{pspicture}
\end{document}