Alex Plunkett, left, and Sean Hart, both of Arlington, Va., join hundreds participating in the annual International Pillow Fight Day on April 5. Massive pillow fights broke out on the Mall in Washington and in cities around the world. (Photo by Marvin Joseph/The Washington Post)

A Filipino teacher checks a picture of a student shown on a tablet that is attached to robot during a graduation ceremony at a school in Taguig City, Philippines, 22 May 2020. At least 179 high school students received their diploma during an online graduation ceremony that was beamed live on Facebook as a measure to prevent the spread of the coronavirus and COVID-19 disease. (Photo by Francis R. Malasig/EPA/EFE)

Children are seen on a bike after Muslims in Nigeria perform Eid prayer following the global outbreak of coronavirus disease (COVID-19) in Nasarawa on May 24, 2020. (Photo by Afolabi Sotunde/Reuters)

Beautician Alex Smith, 26, does the nails of Jules Aspen, 40, at the Madame Beauty salon in Chirton, North Tyneside, UK on July 13, 2020. Nail bars, beauty salons, tattoo and massage studios, physical therapy businesses, spas and piercing services are able to reopen in the latest lifting of restrictions in England. (Photo by Owen Humphreys/PA Images via Getty Images)

Turkey's Merve Aydin cries after she came in last in her women's 800m round 1 heat at the London 2012 Olympic Games at the Olympic Stadium August 8, 2012. (Photo by Lucy Nicholson/Reuters)

A Flemish demonstrator, one of thousands who gathered for a march through Brussels to protest against what the Flemings call their subjucation by the French-speaking Walloons, draws back as he is jeered by a crowd of Walloons on the pavement in a Brussels Street, on October 14, 1962. The Flemish demonstrators clashed with Walloon counter demonstrators as riot police sought to maintain order. The Flemings claim that although they form 60% of the population in Belgium, they are inadequately represented in the government, and they say, the Walloons get most of the top jobs in the armed forces and the diplomatic service. (Photo by AP Photo)

A robot named “Robovie-II”, developed by Japanese robotics research institution ATR, moves around at a grocery store during a shopping assisting experiment by utilizing the robot in an ubiquitous network technology platform in Kyoto, western Japan January 6, 2010. (Photo by Yuriko Nakao/Reuters)

A German rifleman beside the corpse of a French soldier in a trench at Fort Vaux, France, 1916. (Photo by Hulton Archive/Getty Images)