%% 
%%  Ein Beispiel der DANTE-Edition
%%  
%%  2. Auflage
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%%  Beispiel 09-08-42 auf Seite 467.
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%%  Copyright (C) 2016 Herbert Voss
%% 
%%  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.
%% 
%% 
%% ==== 
% Show page(s) 1
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%% 
\documentclass[]{exaarticle}
\pagestyle{empty}
\setlength\textwidth{352.81416pt}
\AtBeginDocument{\setlength\parindent{0pt}}
%StartShownPreambleCommands
\usepackage{mathtools}
%StopShownPreambleCommands
\begin{document}
\[ A = \begin{multlined}[t]
         \framebox[3cm]{Zeile 1} \\ \vdots \\ \framebox[3cm]{Zeile n}
       \end{multlined} =
   B = \begin{multlined}[c]
         \framebox[3cm]{Zeile 1} \\ \vdots \\ \framebox[3cm]{Zeile n}
       \end{multlined} =
   C = \begin{multlined}[b]
         \framebox[3cm]{Zeile 1} \\ \vdots \\ \framebox[3cm]{Zeile n}
       \end{multlined} =
   D \]
\end{document}