Very nice, galactus!
Now I'll show off a bit . . .
\(\displaystyle \begin{array}{|c||c|c|c|}\hline \times & D & E & F \\ \hline \hline A & 1 & 2 & 3 \\ \hline B & 4 & 5 & 6 \\ \hline C & 7 & 8 & 9 & \hline \end{array}\)
The code looks like this:
\begin {array} {|c||c|c|c|} \hline
\times & D & E & F \\ \hline \hline
A & 1 & 2 & 3 \\ \hline
B & 4 & 5 & 6 \\ \hline
C & 7 & 8 & 9 & \hline
\end{array}
Of course, it is all written in one line.