A Russian ground staff member signals to the pilot of a Sukhoi Su-25 fighter jet at the Hmeymim air base near Latakia, Syria, in this handout photograph released by Russia's Defence Ministry October 22, 2015. (Photo by Reuters/Ministry of Defence of the Russian Federation)

A member of the German wireless police picks up signals on the radio equipment he carries on his back, while his colleague takes notes. (Photo by General Photographic Agency/Getty Images). Circa 1925

Japan's computer giant Fujitsu employee displays the world's first personal computer with Intel's RealSense 3D camera “FMV Esprimo” in Tokyo on October 9, 2014. The new desktop PC with 23-inch LCD display can make avatars which mimic the user's look and motion for chatting on the Internet. (Photo by Yoshikazu Tsuno/AFP Photo)

People wear masks to help guard against the Coronavirus in downtown Tehran, Iran, Sunday, February 23, 2020. On Sunday Iran's health ministry raised the death toll from the new virus to 8 people in the country, amid concerns that clusters there, as well as in Italy and South Korea, could signal a serious new stage in its global spread. (Photo by Ebrahim Noroozi/AP Photo)

A dancer from the Trisha Brown Dance Company performs during “Roof Piece” above the High Line park June 9, 2011 in New York City. Roof Piece (1971) consists of nine dancers performing improvised movement signals to each other in a chain on various rooftops overlooking the city. This presentation marked the first full performance of the piece since 1973. (Photo by Mario Tama/Getty Images)

Tara West signals to her partner Natalie Cook during the Bronze final match during the Australian Beach Volleyball Championships at Glenelg Beach on March 13, 2011 in Adelaide, Australia.

Osama bin Laden lookalike Ceara Francisco Helder Braga Fernandes laughs while chatting on the phone in his “Bar do Bin Laden” on April 29, 2014 in Sao Paulo, Brazil. Braga says he was known as the “Beard Man” before 9/11 but became known as a Bin Laden lookalike following the 9/11 attacks. He says he is Christian and continues to play the role to support his business. (Photo by Mario Tama/Getty Images)