\environment columnsets-000

\definecolumnset[example][n=3,page=left,distance=1cm]

\setupcolumnset
  [example]
  [background=contrast]

\definecolor[fakerulecolor][white] \faketriggertrue

\setuphead
  [section]
  [style=\bfd]

\setuplinenumbering
  [style=bold,
   distance=0pt,
   align=inner]

\starttext

\startcolumnset[example]

  \dorecurse{30}{
    \startsection[title=foo #1]
      \startlinenumbering
        \fakewords{50}{100}\par
      \stoplinenumbering
    \stopsection
  }

\stopcolumnset

\stoptext