sequence

Hi, I hope I explain this so you understand. I have seen youtube reviews where they show the LEDs on the DLR lights running a sequence, that is the first top LED illuminates , and then the second comes on, and so forth so that all eventually illuminate. How does that happen? Nick

I want to buy a New or Used Sequence Rear Mini Diffuser for my Genesis Coupe. http://www.importshark.com/store/details.php?image_id=1462&sessionid=0dc890fdc301f98f0d8e5eefc292d795