<<< mml $$\sqrt{\begin{array}{|c|}\hline \phantom{A}\\ \phantom{A}\\ \phantom{A}\\ \hline\end{array}}$$ >>> native [ ESqrt (EArray [ AlignCenter ] [ [ [ EPhantom (EIdentifier "A") ] ] , [ [ EPhantom (EIdentifier "A") ] ] , [ [ EPhantom (EIdentifier "A") ] ] ]) ]