Interpretation: snowballing usury, also known as bean flour cake, is one of the famous traditional snacks in old Beijing, and the finished products have distinct colors of red, white and Huang San. Because the final production process needs to be wrapped in yellow bean, just like the bursts of loess raised by wild donkeys in the countryside when they roll around, it is named "snowballing donkey". It is also a book-"Rolling on a Donkey". This book was written by Lin Haiyin, a famous Taiwan Province woman writer.