\starttext
  \startluacode
    context[[
        \starttabulate[|Tr|]
          \HL
          \NC AABBCC \NC\AR
          \HL[3]
]]

    for i = 1, 4000 do
      context.NC(i)
      context.NC()
      context.AR()
    end

    context[[
      \HL
    \stoptabulate
]]
  \stopluacode
\stoptext