Long Doudou is a winged bean. Also known as quadrangular beans, peach beans, ingot beans, ingot beans, yellow beans, fragrant dragon beans, night beans and so on. A tropical rain forest native to tropical Africa and Southeast Asia. In China, it mainly grows in Hainan and Xishuangbanna. The four-cornered beans are all fried or fried with garlic, which is crisp and refreshing and has a unique flavor. Rich in protein, vitamins and various minerals, it is called green gold because of its high nutritional value.