<<< native
[ EArray
    [ AlignCenter ]
    [ [ [ EGrouped
            [ EIdentifier "A"
            , ESymbol Bin "+"
            , EIdentifier "A"
            , ESymbol Bin "+"
            , EGrouped
                [ EIdentifier "A"
                , ESymbol Bin "+"
                , EIdentifier "A"
                , ESymbol Bin "+"
                , EIdentifier "A"
                ]
            , ESymbol Bin "+"
            , EIdentifier "A"
            ]
        ]
      ]
    , [ [ EGrouped
            [ EIdentifier "A"
            , ESymbol Bin "+"
            , EGrouped
                [ EIdentifier "A"
                , ESymbol Bin "+"
                , EIdentifier "A"
                , ESymbol Bin "+"
                , EIdentifier "A"
                ]
            , ESymbol Bin "+"
            , EIdentifier "A"
            , ESymbol Bin "+"
            , EGrouped
                [ EIdentifier "A"
                , ESymbol Bin "+"
                , EIdentifier "A"
                , ESymbol Bin "+"
                , EIdentifier "A"
                ]
            ]
        ]
      ]
    ]
]
>>> tex
\begin{matrix}
{A + A + {A + A + A} + A} \\
{A + {A + A + A} + A + {A + A + A}}
\end{matrix}