\begin{array}{llllllll}
 & \text{219} & \text{21A} & \text{21B} & \text{21C} & \text{21D} & \text{21E} & \text{21F} \\
\text{0} & \leftarrow & & & \rightharpoonup & \Leftarrow & & \\
\text{1} & \uparrow & & & \rightharpoondown & \Uparrow & & \\
\text{2} & \rightarrow & & & & \Rightarrow & & \\
\text{3} & \downarrow & & & & \Downarrow & & \\
\text{4} & \leftrightarrow & & & & \Leftrightarrow & & \\
\text{5} & \updownarrow & & & & \Updownarrow & & \\
\text{6} & & \mapsto & & & & & \\
\text{7} & \nearrow & & & & & & \\
\text{8} & \searrow & & & & & & \\
\text{9} & \swarrow & \hookleftarrow & & & & & \\
\text{A} & & \hookrightarrow & & & & & \\
\text{B} & & & & & & & \\
\text{C} & & & \leftharpoonup & \rightleftharpoons & & & \\
\text{D} & & & \leftharpoondown & & & & \\
\text{E} & & & & & & & \\
\text{F} & & & & & & & \\
\end{array}
