>function grayscale(y1,y2,n,direction=1) ...
$  loop 0 to n-1;
$  s=#/(n-1); barcolor(rgb(s,s,s));
$  if direction==1 then plotbar(#/n,y1,1/n,y2-y1);
$  else plotbar(1-(#+1)/n,y1,1/n,y2-y1);
$  endif;
$  end;
$endfunction
>function grayscales () ...
$  aspect(2); barstyle("#");
$  window(0,0,1023,1023); margin(0); setplot(0,1,0,1);
$  clg;
$  hold on;
$  grayscale(3/4,1,8,1);
$  grayscale(1/2,3/4,14,-1);
$  grayscale(1/4,1/2,32,1);
$  grayscale(0,1/4,64,-1);
$  hold off;
$endfunction
>grayscales: