%%
%% The LaTeX Companion, 2ed (second printing August 2004)
%%
%% Example 3-5-12 on page 183.
%%
%% Copyright (C) 2004 Frank Mittelbach, Michel Goossens,
%%    Johannes Braams, David Carlisle, and Chris Rowley
%%
%% 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{207.0pt}

\StartShownPreambleCommands
\usepackage{parallel}
\StopShownPreambleCommands
\begin{document}
\begin{Parallel}{}{}
 \ParallelLText{This is text that contains:
                 \[ \sum_{n=1}^x2 a_n \]}
 \ParallelRText{And here is the explanation
            showing some surprising effect.}
\end{Parallel}
\end{document}
