<<< native
[ ERoot
    (EFraction NormalFrac (EIdentifier "x") (ENumber "3"))
    (EGrouped
       [ EIdentifier "x"
       , ESymbol Bin "-"
       , EFraction NormalFrac (EIdentifier "x") (ENumber "3")
       ])
, ESymbol Bin "+"
, ERoot
    (EFraction NormalFrac (EIdentifier "x") (ENumber "3"))
    (EGrouped [ EIdentifier "x" , ESymbol Bin "-" , ENumber "3" ])
, ESymbol Bin "+"
, ERoot
    (EFraction NormalFrac (EIdentifier "x") (ENumber "3"))
    (EGrouped [ EIdentifier "x" , ESymbol Bin "-" , ENumber "3" ])
, ESymbol Bin "+"
, EFraction NormalFrac (EIdentifier "x") (ENumber "3")
]
>>> eqn
"" sup {x over 3} sqrt {x - x over 3} + "" sup {x over 3} sqrt {x - 3} + "" sup {x over 3} sqrt {x - 3} + x over 3