startup

function tunnel(givenLength)
  for index = 1, givenLength do
    turtle.dig()
    turtle.forward()
    turtle.digUp()
  end

  for index = 1, givenLength do
    turtle.back()
  end
end

function prepare()
  local distance = 3

  for index = 1, distance do
    turtle.dig()
    turtle.forward()
    turtle.digUp()
  end
end

function dig(stripLength)
  prepare()
  turtle.turnLeft()
  tunnel(stripLength)
  turtle.turnRight()
  turtle.turnRight()
  tunnel(stripLength)
  turtle.turnLeft()
end

-- Main
print("Tunnel Length:")
local length = read()
print("Tunnel Quantity")
local quantity = read()

for index = 1, quantity do
  dig(length)
end