proc drawgrid (x,y,size:int)
var halfsize :int:=size div 2
if size>10 then
drawbox (x,y,x+size,y+size,10)
drawgrid(x,y,halfsize)
drawgrid(x+halfsize,y+halfsize,halfsize)
drawgrid (x+halfsize,y,halfsize)
drawgrid(x,y+halfsize,halfsize)
end if
end drawgrid

drawgrid (200,100,200)