It's a cool thing, but why does it keep turning up? The Copenhagen Wheel was invented in 2009 and refreshed at the end of last year in a crowdfunding project. A

It's a cool thing, but why does it keep turning up? The Copenhagen Wheel was invented in 2009 and refreshed at the end of last year in a crowdfunding project. And just today an editor pitched me on the idea that e-bikes using this or other methods were about to blow up. E-bike makers have been telling me that for years...