fll

down = 0
slot = 1
count = 0
dir = 1
while true do
  turtle.forward()

  if turtle.detectDown() then
    count = count + 1
  end

  if count > 2 then

    if dir = 1 then
      turtle.turnRight()
      dir = 2
      elseif dir = 2 then
        turtle.turnLeft()
        dir = 1
      end
    turtle.forward()
    turtle.forward()
    count = 0
  end

  while turtle.detectDown() == false do
    count = 0
    turtle.down()
    down = down + 1
  end

  while down > 0 do
    turtle.up()

    while turtle.placeDown() == false do
      slot = slot + 1
        if slot > 16 then
          print("Out of filler")
          return
        end

      turtle.select(slot)
    down = down - 1
    end

  end
end