%% 
%%  The LaTeX Graphics Companion, 2ed (first printing May 2007)
%% 
%%  Example 3-6-10 on page 136.
%% 
%%  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{159.83385pt}
\StartShownPreambleCommands
\usepackage[metapost]{mfpic}
\usepackage{ifthen}

\StopShownPreambleCommands
\begin{document}
\opengraphsfile{tmp}
\begin{mfpic}[1.5]{-40}{50}{-48}{50}
\newcounter{mfcntA}
\newcounter{mfcntB}
\setcounter{mfcntA}{50}
\setcounter{mfcntB}{48}
\whiledo{\themfcntA>1}{%
  \expandafter\curve{(\themfcntA,0),
    (0,\themfcntA),
    (-\themfcntA,0),
    (0,-\themfcntB),
    (\themfcntB,0)}
   \addtocounter{mfcntA}{-2}%
   \addtocounter{mfcntB}{-2}%
 }
\end{mfpic}
\closegraphsfile
\end{document}