Google loves to celebrate holidays and events by displaying custom logos on their website. All of their past custom logos are now available for browsing at Google Logos. I was happy to see that there are several mathematical ones. Here are some that I found (there are many science and technology-related logos that I’m not including here).

April 20, 2009: Zu Zhongzhi’s Birthday – (China)

April 16, 2009: Christiaan Huygens’ Birthday – (Netherlands)

February 14, 2009: Unix Time 1234567890 – (Global)

September 5, 2008: Teacher’s Day – (Poland)

April 24, 2008: Girl’s Day – (Germany) <—this one is mathematical, but the writing is too small for me to read

September 2, 2007: Back to School – (Israel)

September 10, 2005: Teacher’s Day – (China)

May 3, 2005: Teacher’s Day – (US)

April 15, 2005: Leonardo Da Vinci’s Birthday – (Global) <—I never knew Euler and Leonardo had the same birthday

February 4, 2004: Gaston Julia’s Birthday – (Global)

June 16, 2003: MC Escher’s Birthday – (Global)