ComputerCraft Launch

local x = 1
local y = 1

local monitor = peripheral.wrap("top")

monitor.setTextScale(5)
r = 30
rs.setOutput("bottom", false)

for i = -30,30 do

  if i == -20 then
    rs.setOutput("bottom", true)
  end

  monitor.clear()
  monitor.setCursorPos(x,y)

  if i<0 then
    monitor.write("T -00:00:"..r)
  end

  if i>=0 then
    monitor.write("T 00:00:"..i)
  end

  sleep(1)
  r=r-1
end

rs.setOutput("bottom",false)