<<< native
[ EText
    TextNormal
    "Displayed nested fractions are normal size at the first level,\160"
, EFraction
    NormalFrac
    (ESuper (ENumber "1") (ESqrt (ENumber "6")))
    (EGrouped
       [ ESqrt (ENumber "2")
       , ESymbol Bin "+"
       , EFraction
           NormalFrac
           (ENumber "1")
           (EGrouped
              [ ESqrt (ENumber "3")
              , ESymbol Bin "+"
              , EFraction
                  NormalFrac
                  (ENumber "1")
                  (EGrouped
                     [ ESqrt (ENumber "4")
                     , ESymbol Bin "+"
                     , EFraction
                         NormalFrac
                         (ENumber "1")
                         (EGrouped
                            [ ESqrt (ENumber "5")
                            , ESymbol Bin "+"
                            , EFraction
                                NormalFrac
                                (ENumber "1")
                                (EGrouped
                                   [ ESqrt (ENumber "6") , ESymbol Bin "+" , EIdentifier "\8230" ])
                            ])
                     ])
              ])
       ])
, EText
    TextNormal
    "\160script size at second level, and script-script size at all more nested levels."
]
>>> tex
\text{Displayed nested fractions are normal size at the first level,~}\frac{1^{\sqrt{6}}}{\sqrt{2} + \frac{1}{\sqrt{3} + \frac{1}{\sqrt{4} + \frac{1}{\sqrt{5} + \frac{1}{\sqrt{6} + \ldots}}}}}\text{~script size at second level, and script-script size at all more nested levels.}