Coding. In Wuxi, when residents use public bicycles, they usually use the "code up" app to open them. Just scan the QR code on the parking pile to complete the car borrowing process. When returning, they need to return it in the designated area, otherwise they will be charged extra. Wuxi, called "xi" for short and "Liangxi" in ancient times, is a prefecture-level city under the jurisdiction of Jiangsu Province in People's Republic of China (PRC).