startup

function up()
  for i=1,8,1 do
    turtle.digUp()
    turtle.up()
    sleep(0.5)
  end
end

function down()
  for i=1,8,1 do
    turtle.digDown()
    turtle.down()
  end
end

while true do
  up()
  turtle.dig()
  turtle.forward()
  sleep(.1)
  down()
  turtle.dig()
  turtle.forward()
  sleep(.1)
end