local fSlot = 1
local e = true
local w = 63
local l = 63

turtle.select(fSlot)
turtle.refuel(64)
turtle.select(2)
function hasDirt()
    if turtle.getItemCount() == 0 then
        if turtle.getSelectedSlot()+1 == 17 then
            print("No more dirt")
            repeat sleep(1) until turtle.getItemCount(2) > 1
        else
            turtle.select(turtle.getSelectedSlot()+1)
        end
    end
end

for x=1,w do
    for y=1,l do
        turtle.forward()
        turtle.placeDown()
        hasDirt()
    end
    if e  == false then
		turtle.turnLeft()
        turtle.forward()
   		turtle.turnLeft()
	else
		turtle.turnRight()
        turtle.forward()
   		turtle.turnRight()
	end
	e = not e
end