Tennis adopted electronic line calling on clay and created a ball-mark monster

For years, players used ball marks to understand the story of a match on clay. Now, they are being asked not to trust them.
insider.si.edu

Fire Association of Philadelphia Fire Mark

This media is in the public domain (free of copyright restrictions). You can copy, modify, and distribute this work without contacting the Smithsonian. For more information, visit the Smithsonian's ...