English: In 1974, KRON-TV introduced the original version of its current "4" logo, based on the design of the Golden Gate Bridge (the vertical component is a bridge tower, the horizontal component is a portion of the bridge deck, and the curve is a portion of a suspension cable). Station identifications used by the station during the 1970s and 1980s usually depicted the logo hidden in positive space within a full-scale design of the bridge.
Note that it may still be copyrighted in jurisdictions that do not apply the rule of the shorter term for US works (depending on the date of the author's death), such as Canada (50 p.m.a.), Mainland China (50 p.m.a., not Hong Kong or Macao), Germany (70 p.m.a.), Mexico (100 p.m.a.), Switzerland (70 p.m.a.), and other countries with individual treaties.