Fig. 5: Using WeChat groups to share information and exchange foods.

People use Wechat groups to keep updates on the elevator exchange. We can tell from the left screen shot that there were plentiful kinds of goods being exchanged. The residents have become accustomed to proposing a food exchange via online social media at any time. In the right panel, we can see a proposal (in Chinese) on cola for vegetables, cucumbers, or tomatoes, it was responded instantly. This figure is covered by the Creative Commons Attribution 4.0 International License. Reproduced with permission of our anonymous respondents.