tunnel

function digSection()
    for i=1, 5 do
        turtle.dig("right")
        turtle.forward()
    end
end

function fromRight(r)
    turtle.turnLeft()

    for i=1, 2 do
        digSection()
        turtle.turnRight()
        turtle.turnRight()
        turtle.digUp("right")
        turtle.up()
    end
    digSection()
    turtle.turnRight()
    turtle.down()
    turtle.down()

    if r == true then
        turtle.dig("right")
        turtle.forward()
        fromLeft(false)
    end
end

function fromLeft(r)
    turtle.turnRight()
    for i=1, 2 do
        digSection()
        turtle.turnLeft()
        turtle.turnLeft()
        turtle.digUp("right")
        turtle.up()
    end
    digSection()
    turtle.turnLeft()
    turtle.down()
    turtle.down()

    if r == true then
        turtle.dig("right")
        turtle.forward()
        fromRight(false)
    end
end