Introducing a new green bike accessory that harnesses the awesome power of wind as you ride.
You see, the faster you go, the faster it spins, though I can't make scientific claims as to its propulsion capabilities. This is merely a prototype. Haven't figured out how to turn it off either, you park your bike and it keeps on spinning.
As you can see it's actually partly green. And kind of shiny, so it's a safety device as well, making you more visible.
This technology, like many great human advances, was stumbled upon inadvertently. In this case, when I picked my daughter up from school on the bike and she didn't have a free hand to hold her pinwheel.
(Ok, seriously now, who wants to invent a pinwheel-powered bike light? There's an idea for you right there. You're welcome.)