If you spot a line of uniform colored bikes in China like this (picture 1,) don't be confused, feel free to take one and ride on it! These "publicly shared bikes" are trending among Chinese commuters, especially college students. Usually, you can find hundreds of these bikes around a neighborhood. In picture 2, those are all shared bikes provided by different companies.
To use one of these, a biker can simply just take out his/her phone, scan the code on the bike to unlock it, ride it, and park it anywhere after the trip, as long as the traffic rule allows. Billing will be done online automatically, and it's usually ridiculously cheap.
It is not surprising that this great new way of transportation got developed and rapidly became popular in China. It happens when new technologies meet Chinese's "go and get my goal done" culture, or, Chinese pragmatism. People eager to utilize things within their reach to finish tasks on their hands, eventually to reach their life/family goals.