<<< native
[ EArray
    [ AlignCenter , AlignCenter , AlignCenter ]
    [ [ [ EIdentifier "H" ]
      , [ ESymbol Accent "\8594" ]
      , [ EIdentifier "G" ]
      ]
    , [ [ ESymbol Rel "\8595" ]
      , [ ESpace (3 % 1) ]
      , [ ESymbol Rel "\8595" ]
      ]
    , [ [ EIdentifier "K" ]
      , [ ESymbol Accent "\8594" ]
      , [ EIdentifier "L" ]
      ]
    ]
]
>>> eqn
matrix{
ccol{ H above \[u2193] above K }
ccol{ -> above {fwd 300} above -> }
ccol{ G above \[u2193] above L }
}