<<< mml $\begin{array}{|cccc|}\hline \text{Top}& 3& \frac{a+1}{2}& \stackrel{\frac{a+1}{2}}{y}\\ \text{Bottom}& 3& \frac{a+1}{2}& \stackrel{\frac{a+1}{2}}{y}\\ \text{Center}& 3& \frac{a+1}{2}& \stackrel{\frac{a+1}{2}}{y}\\ \text{Baseline}& 3& \frac{a+1}{2}& \stackrel{\frac{a+1}{2}}{y}\\ \hline\end{array}$ >>> native [ EArray [ AlignCenter , AlignCenter , AlignCenter , AlignCenter ] [ [ [ EText TextNormal "Top" ] , [ ENumber "3" ] , [ EFraction NormalFrac (EGrouped [ EIdentifier "a" , ESymbol Bin "+" , ENumber "1" ]) (ENumber "2") ] , [ EOver False (EIdentifier "y") (EFraction NormalFrac (EGrouped [ EIdentifier "a" , ESymbol Bin "+" , ENumber "1" ]) (ENumber "2")) ] ] , [ [ EText TextNormal "Bottom" ] , [ ENumber "3" ] , [ EFraction NormalFrac (EGrouped [ EIdentifier "a" , ESymbol Bin "+" , ENumber "1" ]) (ENumber "2") ] , [ EOver False (EIdentifier "y") (EFraction NormalFrac (EGrouped [ EIdentifier "a" , ESymbol Bin "+" , ENumber "1" ]) (ENumber "2")) ] ] , [ [ EText TextNormal "Center" ] , [ ENumber "3" ] , [ EFraction NormalFrac (EGrouped [ EIdentifier "a" , ESymbol Bin "+" , ENumber "1" ]) (ENumber "2") ] , [ EOver False (EIdentifier "y") (EFraction NormalFrac (EGrouped [ EIdentifier "a" , ESymbol Bin "+" , ENumber "1" ]) (ENumber "2")) ] ] , [ [ EText TextNormal "Baseline" ] , [ ENumber "3" ] , [ EFraction NormalFrac (EGrouped [ EIdentifier "a" , ESymbol Bin "+" , ENumber "1" ]) (ENumber "2") ] , [ EOver False (EIdentifier "y") (EFraction NormalFrac (EGrouped [ EIdentifier "a" , ESymbol Bin "+" , ENumber "1" ]) (ENumber "2")) ] ] ] ]