Mario Huettenhofer, chief of the German company 3D Fab, presents his own face as 3d print during the international fairs FabCon 3.D and Rapid.Tech in Erfurt, Germany, Thursday, May 15, 2014. 130 exhibitors from all over the world present the entire world of 3D printing. The trade fairs are accompanied by specialist programs featuring 80 scientists, practitioners and trend analysts from ten countries, who will explain the latest findings, trends and applications for additive processes in industry and for 3D printing in the private sector to newcomers, experts and consumers alike. (Photo by Jens Meyer/AP Photo)

Visitors look at a giant puppet of a grandmother sleeping on a bed inside St George's Hall in Liverpool, northern England July 23, 2014. The grandmother is one of two giant models made for a World War I commemorative event. (Photo by Nigel Roddis/Reuters)

Horse riders perform with guns during the El-Jadida International Horse Show in El-Jadida, south of Casablanca, Morocco, October 15, 2016. (Photo by Youssef Boudlal/Reuters)

Men help a woman affected by tear gas used by National Police officers to disperse a demonstration of supporters of Fanmi Lavalas political party in the streets of Port-au-Prince, Haiti, November 22, 2016. (Photo by Andres Martinez Casares/Reuters)

Anti-pollution protesters wearing traditional costumes and contemporary gas masks ride bicycles in the Qingming Grand river park in Kaifeng, Henan Province, China on January 1, 2017. The Beijing Municipal Environmental Protection Bureau extended an “orange alert” for heavy air pollution for three more days. (Photo by SIPA Asia/Rex Features/Shutterstock)

St Andrews University students skinny dip in the sea as May Day celebrations in St Andrews, Scotland on April 30, 2017. Hundreds of revellers ditched their clothes and bravely jumped into the bitterly cold North Sea. (Photo by Alamy Stock Photos)

Athletes from Australia's Olympic team going to the 2016 Olympics in Rio present their uniforms alongside Brazilian Samba dancer Sashya Jay at an official unveiling ceremony at Sydney's Bondi Beach, March 30, 2016. (Photo by Jason Reed/Reuters)

Performers are reflected in a displayed vehicle before going onto the stage during the Auto China 2016 auto show in Beijing, China, April 29, 2016. (Photo by Damir Sagolj/Reuters)