\setupinteraction
  [state=start]

\setupsubpagenumber
  [state=start]

\setuplayout
  [middle]

\setuppapersize
  [S4][S4]

\startsetups bars
    \ruledvbox to \textheight \bgroup
        a \ruledhbox{\interactionbar[a]}\vss
        b \ruledhbox{\interactionbar[b]}\vss
        c \ruledhbox{\interactionbar[c]}\vss
        d \ruledhbox{\interactionbar[d]}\vss
        e \ruledhbox{\interactionbar[e]}\vss
        f \ruledhbox{\interactionbar[f]}\vss
        g \ruledhbox{\interactionbar[g]}\vss
    \egroup
\stopsetups

\setuptexttexts[\setups{bars}]

\starttext
    \dorecurse {12} {
        \startstandardmakeup
        \stopstandardmakeup
    }
\stoptext
