Adidas says that its new $240 UltraBOOST Uncaged sneakers were "inspired by consumer customisation, and a global trend that started last year". That global trend wasn't actually something that Adidas had forecast, though -- and it started because sneakerheads were buying the company's original UltraBOOST running shoes and cutting off the plastic mid-foot cage to show off the knitted fabric underneath. So, Adidas took the hint and made its own.