Robot couple Xiaolan (L) and Xiaotao carry trays of food at a restaurant in Jinhua, Zhejiang province, China, May 18, 2015. The restaurant, which opened on Monday, has two robots delivering food for customers. The robots were designed as a couple, Xiaolan and Xiaotao, according to local media. (Photo by Reuters/Stringer)

Lightning strikes the Willis Tower (formerly Sears Tower) in downtown on June 12, 2013 in Chicago, Illinois. (Photo by Scott Olson/Getty Images)

A prototype battery-powered plane, called Greased Lightning or GL-10 is pictured flying at NASA's Langley Research Center in this undated handout photo obtained by Reuters May 1, 2015. The plane, which has 10 engines and can take off like a helicopter and fly efficiently like an aircraft, is currently in the design and testing phase. (Photo by Reuters/NASA)

A topless woman walks through Bryant Park following the protest march called the GoTopless Day Parade Sunday, August 23, 2015, in New York. The parade took to the streets to counter critics who are complaining about topless tip-seekers in Times Square. Appearing bare-breasted is legal in New York. But Mayor Bill de Blasio and police Commissioner Bill Bratton say the body-painted women in the square who take photos with tourists are a nuisance. (Photo by Kevin Hagen/AP Photo)

A model presents a creation by Colombian brand Elena Plus Clothing at Colombiamoda during Medellin's fashion week in Itagui municipality near Medellin, Antioquia department, Colombia, on July 24, 2017. Colombiamoda will take place between the 24th and 27th of July. (Photo by Joaquin Sarmiento/AFP Photo)

Hailee Steinfeld performs at the American Music Awards at the Microsoft Theater on Sunday, November 19, 2017, in Los Angeles. (Photo by Matt Sayles/Invision/AP Photo)

Two women kiss each other during a flashmob on the ocassion of the International Day Against Homophobia, Transphobia and Biphobia in Pamplona, Navarra, Spain, 17 May 2017. The International Day Against Homophobia, Transphobia and Biphobia is held every year on 17 May. (Photo by Villar Lopez/EPA/EFE)

Animal rights activists perform, demanding the abolition of bullfights, during a demonstration in Medellin, Colombia February 11, 2018. The Colombian Constitutional Court overruled on February 7, 2018, a judgment that allowed to hold a referendum regarding bullfights. (Photo by Fredy Builes/Reuters)