<<< native
[ EArray
    [ AlignCenter , AlignCenter , AlignCenter ]
    [ [ [ EOver
            False (EIdentifier "HT") (EPhantom (EText TextNormal "fail"))
        ]
      , [ ESymbol Rel "=" ]
      , [ EIdentifier "TH" ]
      ]
    ]
]
>>> eqn
matrix{
ccol{ {HT to {hphantom {roman "fail"}}} }
ccol{ = }
ccol{ TH }
}