filler

local n=1
local x=1
for y=1,turtle.getFuelLevel (),1 do
    turtle.select(n)
    if turtle.getItemCount(n) == 0
        then n=n+1
    end
    if turtle.detect()
        then
        if x==1 then
            turtle.turnLeft()
            turtle.forward()
            turtle.placeDown()
            turtle.turnLeft()
            x=x+1
            else
            turtle.turnRight()
            turtle.forward()
            turtle.placeDown()
            turtle.turnRight()
            x=x-1
            end
    end
    if turtle.detectDown()
        then turtle.forward()
        else turtle.placeDown()
    end
    if n==17 then
        break
    end
end