A MAN pedals a brand-new, orange and silver bicycle to his office door. He dismounts in the middle of the pavement, flicks down the kickstand and disAPPears inside. A woman approaches and waves her smartphone over a QR code near the rear mudguard. The lock snaps open and off she rides. These days, China’s once bicycle-clogged streets are choked with cars. But some urbanites are getting back on two (motorless) wheels, lured by the ease of using shared “dockless” bikes controlled by high-tech gadgetry.