The Google logo appears in numerous settings to identify the search engine company. Google has used several logos over its history, with the first logo created by Sergey Brin using GIMP. A revised logo debuted on September 1, 2015. The previous logo, with slight modifications between 1999 and 2013, was designed by Ruth Kedar, with a wordmark based on the Catull font, an old style serif typeface designed by Gustav Jaeger for the Berthold Type Foundry in 1982.The company also includes various modifications or humorous features, such as modifications of their logo for use on holidays, birthdays of famous people, and major events, such as the Olympics. These special logos, some designed by Dennis Hwang, have become known as Google Doodles.