%%
%% The LaTeX Companion, 3ed
%%
%% Example 11-3-8 on page II-158 in "delarray --- Delimiters surrounding an array".
%%
%% Copyright (C) 2022 Frank Mittelbach
%%
%% It may be distributed and/or modified under the conditions
%% of the LaTeX Project Public License, either version 1.3c
%% of this license or (at your option) any later version.
%%
%% See https://www.latex-project.org/lppl.txt for details.
%%

\documentclass{tlc3examargin}
\pagestyle{empty}
\setcounter{page}{6}
\setlength\textwidth{159.0pt}
%StartShownPreambleCommands
\usepackage{delarray}
%StopShownPreambleCommands

\begin{document}
\[ \mathcal{Q} =
\begin{array}[t] ( {cc} ) X & Y \end{array}
\begin{array}[t] [ {cc} ] A & B \\ C & D  \end{array}
\begin{array}[b] \lgroup{c}\rgroup L \\ M \end{array}
\]
\end{document}