\begin{matrix}
 & \text{20D} & \text{20E} & \text{20F} \\
\text{0} & & & \\
\text{1} & & \overleftrightarrow{} & @ \\
\text{2} & & & @ \\
\text{3} & & & @ \\
\text{4} & & \lbrack?\rbrack & @ \\
\text{5} & & & @ \\
\text{6} & \overleftarrow{} & \lbrack?\rbrack & @ \\
\text{7} & \vec{} & \lbrack?\rbrack & @ \\
\text{8} & & & @ \\
\text{9} & & & @ \\
\text{A} & & & @ \\
\text{B} & \dddot{} & & @ \\
\text{C} & \ddddot{} & & @ \\
\text{D} & & & @ \\
\text{E} & & \underleftarrow{} & @ \\
\text{F} & & \underrightarrow{} & @ \\
\end{matrix}
