%%
%%  The LaTeX Graphics Companion, 2ed (first printing May 2007)
%%
%%  Example 5-13-31 on page 294.
%%
%%  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{ttctexa}
\pagestyle{empty}
\setcounter{page}{6}
\setlength\textwidth{183.83385pt}
\StartShownPreambleCommands
\usepackage{pstricks}
\StopShownPreambleCommands
\begin{document}
\begin{pspicture}[showgrid=true](3,3)
 \pscustom{%
    \code{newpath}
    \rcoor(0.5,0.5)(0,2)(2,0)(0,-2)
    \code{
       moveto rlineto rlineto rlineto
       closepath
       2 setlinejoin 7.5 setlinewidth
       stroke}}
\end{pspicture}
\end{document}