\noindent
\begin{center}
\begin{tabular}{|l|c|c|l|}
\hline
\multicolumn{4}{|c|}{{\vrule height12pt width0pt depth3.5pt\Large
Troff Special Symbols Supported}}\\ 
\hline\hline
symbol&	 troff name&supported&\multicolumn{1}{|c|}{description}\\
\hline
$\bullet$&$\backslash$(bu&        x&              bullet\\
---&$\backslash$(em&	        x&		em-dash\\
\regmark&$\backslash$(rg&	x&		registered\\
\tm&	$\backslash$(tm&	x&		trademark\\
\tm&	$\backslash$*(Tm&	x&		trademark (alternative form)\\
\copyright&$\backslash$(co&	x&		copyright\\
\dag&	$\backslash$(dg&	x&		dagger\\
\ddag&	$\backslash$(dd&	x&		double dagger\\
\cents&	$\backslash$(ct&	x&		cent sign\\
$\circ$&$\backslash$(de&	x&		degree\\
'&	$\backslash$fm&	        x&		footmark\\
\S&     $\backslash$(sc&        x&              paragraph mark\\
\hline\hline
x&\multicolumn{3}{|l|}{implemented}\\
\hline
\end{tabular}
\end{center}
\medskip