\starttext
    \startMPpage
        fill   fullsquare scaled 4cm withpen pencircle scaled 1cm;
        draw   fullsquare scaled 4cm withpen pencircle scaled 1cm;
    \stopMPpage
    \startMPpage
        fillup fullsquare scaled 4cm withpen pencircle scaled 1cm;
    \stopMPpage
\stoptext

