<<< native
[ EArray
    [ AlignRight , AlignRight ]
    [ [ [ EGrouped
            [ EPhantom (EText TextNormal "fail") , EIdentifier "H" ]
        ]
      , [ EIdentifier "A" ]
      ]
    , [ [ EGrouped
            [ EPhantom (EText TextNormal "fail") , EIdentifier "T" ]
        ]
      , [ EIdentifier "I" ]
      ]
    , [ [ EGrouped
            [ EPhantom (EText TextNormal "fail") , EIdentifier "U" ]
        ]
      , [ EIdentifier "Y" ]
      ]
    ]
, ESymbol Rel "="
, EArray
    [ AlignLeft , AlignLeft ]
    [ [ [ EIdentifier "A" ]
      , [ EGrouped
            [ EIdentifier "H" , EPhantom (EText TextNormal "fail") ]
        ]
      ]
    , [ [ EIdentifier "I" ]
      , [ EGrouped
            [ EIdentifier "T" , EPhantom (EText TextNormal "fail") ]
        ]
      ]
    , [ [ EIdentifier "Y" ]
      , [ EGrouped
            [ EIdentifier "U" , EPhantom (EText TextNormal "fail") ]
        ]
      ]
    ]
]
>>> eqn
matrix{
rcol{ {hphantom {roman "fail"} H} above {hphantom {roman "fail"} T} above {hphantom {roman "fail"} U} }
rcol{ A above I above Y }
} = matrix{
lcol{ A above I above Y }
lcol{ {H hphantom {roman "fail"}} above {T hphantom {roman "fail"}} above {U hphantom {roman "fail"}} }
}