% context --autopdf=auto --arrange --arguments=schema=2\*4,pages=16

\def\Schema{\doifelsedocumentargument{schema}{\getdocumentargument{schema}}{1*8}}
\def\Pages{\doifelsedocumentargument{numberofpages}{\getdocumentargument{numberofpages}}{16}}

\setuppapersize[A9,landscape][A7,landscape]

\setuparranging[\Schema]

\setupbodyfont[ss,10pt]

\setuplayout[margin=0pt, width=fit, header=2.8ex, footer=2.8ex]
\setupalign[middle,hilo]
\setuppagenumbering [alternative=doublesided,location=footer]
\setupheadertexts[\CONTEXT\ imposition test]

\showframe
\setupbackgrounds [text][text][background=color,backgroundcolor=lightgray]

% Where the block of pages is placed on the sheet
% (relevant if there is space left over.)
\setuplayout [location=middle,marking=on]

\startbuffer[Fakepage]
    \strut
    \blank
    \bold{[\Schema]}
    \vfill
    This is page \recurselevel
    \vfill
\stopbuffer

\starttext
\dorecurse{\Pages}{\getbuffer[Fakepage]\page}
\stoptext
