%% 
%%  The LaTeX Graphics Companion, 2ed (first printing May 2007)
%% 
%%  Example 5-7-14 on page 246.
%% 
%%  Copyright (C) 2007 Michel Goossens, Frank Mittelbach, Denis Roegel, Sebastian Rahtz, Herbert Vo\ss 
%% 
%%  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.
%% 

\documentclass{ttctexagray}
\pagestyle{empty}
\setcounter{page}{6}
\setlength\textwidth{159.83385pt}
\StartShownPreambleCommands
\usepackage{pstricks}
\StopShownPreambleCommands
\begin{document}
\begin{pspicture}[showgrid=true](3,3)
  \psccurve*[linecolor=cyan]%
     (1.5,1.5)(2.5,1.5)(2.5,2.5)(1.5,2.5)
  \psccurve[showpoints=true]%
     (1.5,1.5)(2.5,1.5)(2.5,2.5)(1.5,2.5)
  \psccurve[showpoints=true,linecolor=red,
     linewidth=1.5pt](.5,0)(2.5,1)(2.5,0)(.5,1)
\end{pspicture}
\end{document}