%% 
%%  A DANTE-Edition example
%% 
%%  Example 33-03-18 on page 694.
%% 
%%  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{pst-optic}

\begin{document}
\begin{pspicture}(-7,0.5)(5,5.5)
  \pnode(-3,1){A}\pnode(1,1){B}\pnode(-1,5){C}
  \uput[-135](A){A}\uput[-45](B){B}\uput[30](C){C}
  \pspolygon[fillcolor=lightgray,fillstyle=solid,linecolor=blue](A)(B)(C)
  \psset{linecolor=red,arrowsize=3pt,arrows=->}
  \multido{\rA=0.6+0.2,\rB=1.5+0.2}{7}{%
    \refractionRay(-6,\rA)(-4,\rB)(C)(A){1}{1.5}{END}
    \arrowLine(-6,\rA)(END){2}\ABinterCD(END)(END')(C)(B){Out}
    \arrowLine(END)(Out){1}   \refractionRay(END)(Out)(C)(B){1.5}{1}{Q}
    \psline(Q)(Q')            \psOutLine[length=3](Q)(Q'){End} }
\end{pspicture}
\end{document}
