u := 5mm;
defaultfont := "pplr";
defaultscale := 12pt/fontsize defaultfont;

beginfig(1);
path p;  
p := unitsquare xscaled 8u yscaled 3u;

fill p shifted(11u,6u) withcolor 0.8white;
fill p shifted(0,6u) withcolor 0.8white;
draw p shifted(0,u) withcolor 0.8white;

drawarrow (4u,6u)--(4u,4u);
drawarrow (4u,1u)--(4u,0);
drawarrow (11u,7.5u){-1,.5}..{-1,-.5}(8u,7.5u);

label("unten",(4u,2.5u));
label("oben",(4u,7.5u));

defaultfont:="pcrr";
label("rechts",(15u,7.5u));

endfig;
end;