Toto, Japan's foremost toilet manufacturer, has made a motorized tricycle that runs on human crap. The saddle is a functional toilet, and if you can muster up enough colonic motility to keep up a steady stream, you could travel the world.
As the person drives, he can poop into the bowl, and that poop will be turned into fuel for the car. The motorcycle will be making its way from Kyushu to Tokyo over the next month.The Presurfer
