Photo taken on Dec. 28, 2018 shows inner painted snuff bottles created by teacher Yin Jianqing at Hebei College of Industry and Technology in Shijiazhuang, north China's Hebei Province, Dec. 28, 2018. The college takes intangible cultural heritages such as techniques of pyrograph and inner painting into school courses in recent years. (Xinhua/Liang Zidong)