What is a peep show? In what era?

The peep show, also called pull-tab, is one of the early folk acrobatics and belongs to the "hanging" line in the Jianghu. 360 lines, each line has its origin. According to textual research, the peep show was invented by Nanjing people in the middle of Qing Dynasty, so it was named because the convex mirrors and pictures used were imported from foreign countries. In the tenth year of Daoguang reign (1830), Lu (1) recorded: "Jiangning (now Nanjing) artificial wooden box decorated with flowers, trees, birds, fish, gods and monsters. There is a round hole outside, which is covered with five-color hawksbill (glass). At first glance, the obstacles are small.