Competitors take part in the contest of the Gansu division of 18th China Adolescent Robotics Competition in Yongjing County, northwest China's Gansu Province, April 13, 2018. Sixteen teams attended the contest here on Friday. (Xinhua/Chen Bin)

Competitors take part in the contest of the Gansu division of 18th China Adolescent Robotics Competition in Yongjing County, northwest China's Gansu Province, April 13, 2018. Sixteen teams attended the contest here on Friday. (Xinhua/Chen Bin)

Competitors take part in the contest of the Gansu division of 18th China Adolescent Robotics Competition in Yongjing County, northwest China's Gansu Province, April 13, 2018. Sixteen teams attended the contest here on Friday. (Xinhua/Chen Bin)