redstone.setOutput("left", true)
local mode = 0

function getGravelCount()
	return turtle.getItemCount(1) + turtle.getItemCount(2) + turtle.getItemCount(3) +
		turtle.getItemCount(4) + turtle.getItemCount(5) + turtle.getItemCount(6) +
			turtle.getItemCount(7) + turtle.getItemCount(8) + turtle.getItemCount(9)
end

function moses()
	while not turtle.detectDown() and getGravelCount() > 0 do
		turtle.placeDown()
	end
	turtle.forward()
end

while true do
  if mode == 0 then
  	if getGravelCount() == (9*64) then
  		mode = 1
  	elseif getGravelCount() < (9*64) then
  		os.sleep(2)
  	end
  end
  if mode == 1 then
  	while getGravelCount() > 0 do
  		moses()
  	end
  	turtle.turnLeft()
  	turtle.turnLeft()
  	while not turtle.detect() do
  		turtle.forward()
  	end
  	turtle.turnLeft()
  	turtle.turnLeft()
  	mode = 0
  end
end