Google, in Germany and a bunch of other select countries, has a special birthday logo for the 169th birthday of Friedrich Nietzsche.
Friedrich Nietzsche was most well known for his philosophical belief in the Will to Power and Eternal recurrence. The logo represents a person trying to reach the highest possible position in life because of the achievement, ambition and strive in human nature.
Google said on Google+:
Forum discussion at Google+ and Google Web Search Help.