Blinker

local mon = peripheral.wrap("back")

mon.write = function (...)
  mon.callRemote("wrap", ...)
end

mon.clear = function () mon.callRemote("clear") end

mon.setCursorPos = function (...)
  mon.callRemote("setCursorPos", "?", ...)
end

local messages = {
  "Do not enter!", " ", " ", "Or else! ", " "," " }

repeat
  for i = 1, #messages do
    mon.setCursorPos(1, 1)
    mon.clear()
    mon.write("Server Room")
    mon.setCursorPos(1, 2)
    mon.write(messages[i])
    sleep(1)
  end
until cows_come_home