1x2 tunnel

for i=1,16 do
    if turtle.getItemCount() == 0 then turtle.select(turtle.getSelectedSlot() + 1) end
    turtle.dig()
    turtle.digUp()
    turtle.forward()
    turtle.turnRight()
    turtle.place()
    turtle.up()
    turtle.place()
    turtle.turnRight()
    turtle.turnRight()
    turtle.place()
    turtle.placeUp()
    turtle.down()
    turtle.place()
    turtle.placeDown()
    turtle.turnRight()
end