local mon = peripheral.wrap("top")
local mx, my = mon.getSize()

mon.clear()
term.clear()

-- This function will return when any key other than ESC is pressed
function waitForEsc()
	while true do
		local e, key = os.pullEvent("key")
		if key ~= 1 then
			-- It wasn't escape
			return true
		end
	end
end

-- This function actually does the screensaver, and won't return on its own
function screensaver()
	while true do
		local x = math.random(1,mx)
		local y = math.random(1,my)
		mon.setCursorPos(x,y)
		mon.write("o")
		sleep(2)
		mon.clear()
		sleep(2)
	end
end

-- Now run both functions
parallel.waitForAny(function() screensaver() end,function() waitForEsc() end)

-- Something returned if we got here
term.clear()
term.setCursorPos(1,1)