Obviously not at SMD scale, but I have seen fun videos with seemingly simple circuits with LEDs and switches connected in series and they behaved completely dif

Obviously not at SMD scale, but I have seen fun videos with seemingly simple circuits with LEDs and switches connected in series and they behaved completely differently (eg. each switch connected in series controlled other LED). It turned out that switches and LEDs have been modified with clever frequency generators and filter circuits. edit: https://www.youtube.com/watch?v=RkTvDjhImwo https://www.youtube.com/watch?v=RkTvDjhImwo