\starttext

    \input zapf

    \startnarrower
        \startitemize[columns,two,packed][before=,after=]
            \dorecurse{10}{\startitem item #1 \stopitem}
        \stopitemize
    \stopnarrower

    \input zapf

    \startnarrower
        \startitemize[columns,two][before=,after=]
            \dorecurse{10}{\startitem item #1 \stopitem}
        \stopitemize
    \stopnarrower

    \input zapf

    \startnarrower
        \startitemize[columns,two]
            \dorecurse{10}{\startitem item #1 \stopitem}
        \stopitemize
    \stopnarrower

    \input zapf

\stoptext
