<<< mml $\begin{array}{ccc}H& \to & G\\ \downarrow & & \downarrow \\ K& \to & L\end{array}$ >>> native [ EArray [ AlignCenter , AlignCenter , AlignCenter ] [ [ [ EIdentifier "H" ] , [ ESymbol Accent "\8594" ] , [ EIdentifier "G" ] ] , [ [ ESymbol Rel "\8595" ] , [ ESpace (3 % 1) ] , [ ESymbol Rel "\8595" ] ] , [ [ EIdentifier "K" ] , [ ESymbol Accent "\8594" ] , [ EIdentifier "L" ] ] ] ]