fence

function place32()
  for i=1,31 do
    if turtle.forward() = true do
      turtle.forward()
    else
      turtle.dig()
      turtle.forward()
    end
    if turtle.placeDown() = true do
      turtle.placeDown()
    else
      turtle.digDown()
      turtle.placeDown()
  end
end

turtle.select(1)
place32()
turtle.turnRight()
place32()
turtle.turnRight()
turtle.select(2)
place32()
turtle.turnRight()
place32()
turtle.turnRight()