shaft

while true do
    turtle.dig()
    turtle.forward()
    turtle.turnLeft()

    for i=1,8,1 do
        turtle.dig()
        turtle.digUp()
        turtle.digDown()
        turtle.forward()
        turtle.dig()
        turtle.digUp()
        turtle.digDown()
    end

    turtle.down()
    turtle.turnRight()
    turtle.dig()
    turtle.forward()
    turtle.turnRight()

    for i=1,8,1 do
        turtle.dig()
        turtle.digUp()
        turtle.digDown()
        turtle.forward()
        turtle.dig()
        turtle.digUp()
        turtle.digDown()
    end
end