local monitor = peripheral.wrap("top")
local function fillScreen(color)
  monitor.setBackgroundColor(color)
  local x,y = monitor.getSize()
  for i=1, y do
    monitor.setCursorPos(1,i)
    monitor.write(string.rep(" ", x))
  end
end

local function rsTimer(value)
  while true do
    rs.setBundledOutput("bottom", value)
    sleep(.5)
    rs.setBundledOutput("bottom", 0)
    sleep(.5)
  end
end

local selection = 1

while true do
  local event = os.pullEvent()
  if event == "monitor_touch" then
    if selection == 1 then
      fillScreen(colors.green)
      selection = 2
    else
      fillScreen(colors.blue)
      selection = 1
    end
  elseif event == "redstone" then
    while rs.getInput("left") do
      rsTimer(selection)
    end
  end
  sleep(0)
end