%% 
%%  The LaTeX Graphics Companion, 2ed (first printing May 2007)
%% 
%%  Example 8-2-18 on page 528.
%% 
%%  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{348.0pt}
\AtBeginDocument{\setlength\unitlength{0.09pt}}
%% Small unitlength may result in diagonal connections to vanish unless
%% a package like epic, eepic, or pict2e is being used that supports small lines
%%
\usepackage{pict2e}

\StartShownPreambleCommands
\usepackage{epic,hetarom}
\StopShownPreambleCommands
\begin{document}
\threehetero      {1==S}     {3Sa==H$_3$C;3Sb==H$_3$C}
\fourhetero       {1==O;2==O}{4Sa==COOH;4Sb==COOH}
\fiveheterov[eb]  {1==N}     {1D==O;4SA==MeO;4SB==OMe;5==Cl}
\sixheterov [c]   {1==N}     {1==Cl;4==F;2==CH$_3$}
\end{document}