%%
%% The LaTeX Companion, 3ed
%%
%% Example 6-6-5 on page I-471 in "hhline --- Combining horizontal and vertical lines".
%%
%% 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{tlc3exa}
\pagestyle{empty}
\setcounter{page}{6}
\setlength\textwidth{111.0pt}

%StartShownPreambleCommands
\usepackage{hhline}  \setlength\arrayrulewidth{.8pt}
\renewcommand\arraystretch{1.5}
%StopShownPreambleCommands

\begin{document}
                              % columns:    1 2     3 4      5
\begin{tabular}{||cc||c|c||c}   \hhline{|t: = = :t: = =  :t|  }
 a & b & c & d               \\ \hhline{|:  = = :|  ~|~  | |  }
 1 & 2 & 3 & 4               \\ \hhline{ #  = =  #  ~|=  :b| -}
 i & j & k & l
   & \multicolumn{1}{c|}{?}  \\ \hhline{||  - - ||  - -      -}
 w & x & y & z               \\ \hhline{|b: = = :b: = =  :b|  }
\end{tabular}
\end{document}
