An unknown number of guns are being built with the mechanisms, causing problems for the police and ATF officials. Photo: An ATF agent holds a generic unfinished receiver, back, and one that has been manufactured, front, at an ATF field office in Washington, on May 06, 2014. The ATF is trying to crack down on the trade in the makeshift guns by targeting shops and individuals who offer to turn the unfinished receivers into functional pieces for firearms. (Photo by Bill O'Leary/The Washington Post)

A steam traction engine with a broken rear axle in Pall Mall, London. (Photo by Topical Press Agency/Getty Images). November 1923

Toyota Motor unveils a concept car the “PM”, is on display at a press preview for the Tokyo Motor Show in Makuhari, east of Tokyo October 23, 2003. PM is a single seater personal vehicle whose cabin posture changes from upright to reclined as speed increases. (Photo by Koichi Kamoshida/Getty Images)

A girl picks catkins at a field amid the COVID-19 pandemic in Sarighat, on the outskirts of Dhaka, Bangladesh, October 2, 2020. (Photo by Mohammad Ponir Hossain/Reuters)

Juventus' Italian forward Cristiana Girelli celebrates after scoring an equalizer during the UEFA Women's Champions League Group A football match between Juventus and Wolfsburg on November 09, 2021 at the Juventus stadium in Turin. (Photo by Marco Bertorello/AFP Photo)

A woman carries a 'Climate Clock' as activists mark the start of Climate Week in New York during a demonstration calling for the U.S. government to take action on climate change and reject the use of fossil fuels in New York City, New York, U.S., September 17, 2023. (Photo by Eduardo Munoz/Reuters)

Dallas Cowboys cheerleaders entertain the crowds during a match against Washington Football Team at AT&T Stadium on December 26, 2021 in Arlington, Texas. (Photo by Tim Heitman/USA TODAY Sports)

A pedestrian waits for a bus in front of a “Living Wall” art project, produced in collaboration with The National Portrait Galler and the Earls Court Development Company, in west London on May 26, 2022. (Photo by Adrian Dennis/AFP Photo)