Left Nether Highway

slot = 1

for i = 1, 16, 1 do

    for i = 1, 64, 1 do
        turtle.turnLeft()
        turtle.place()
        turtle.up()
        turtle.place()
        turtle.placeUp()
        turtle.down()
        turtle.turnRight()
        turtle.forward()
    end
    slot = slot + 1
    turtle.select(int(slot))
end