function detectdown()
        turtle.select(15)
        while turtle.compareDown() do
                turtle.digDown()
                turtle.down()
        end
end
function cut()
        turtle.dig()
        turtle.turnRight()
        turtle.dig()
        turtle.turnLeft()
end
turtle.dig()
turtle.forward()
turtle.select(15)
while turtle.compareUp() do
        cut()
        turtle.digUp()
        turtle.up()
end
cut()
turtle.forward()
turtle.turnRight()
turtle.dig()
turtle.forward()
detectdown()