A photo showing pupils stacked on top of each other three-layers high with their teacher sitting on them has attracted public attention, Xiaoxiang Morning News reported on Thursday.

Some parents of the children in a kindergarten in Changsha, capital of Hunan province, received the photo of the “human chair” from the teacher on Wednesday and said they were worried their kids could have been injured.

The kindergarten said the lesson was to teach the children to combat stress through teamwork.