The city even has a tunnel for the cars to drive through, which is simply PVC pipe covered by mulch. Also, cement blocks painted and buried to create the roadway. (look out for spiders and snakes that may take up shelter in the pipe!
Concept from Korean designer Sungho Lee: Intuitively, I love it! How clever! I want to make a bunch of my own—as I imagine Mr. Lee did—by cutting up some paper clips, clipping the leads on a bunch of LEDs, and soldering the one to the other.