These photos of Google's and Microsoft's CEOs show how far they've taken their rivalry

Google and Microsoft each held their annual developer conferences the same week this year.It's a sign of the rivalry between the two tech giants.Google and Microsoft both revealed new mottos during the events, and the slogans were eerily similar.Visit Business Insider's homepage for more stories.The rivalry between Google and Microsoft is decades long, legendary and not ending any time soon. The two companies compete over everything: cloud computing, employees, office productivity software, search engines, new technologies like artificial intelligence and personal assistants.This week, they even competed for developer love. Each one held their huge developer conferences in rival cities, during the same week. It's not by accident. They are forcing developers to choose. Microsoft Buildis taking place this week in Seattle. Google i/o is taking place this week in Mountain View, California.And each of their CEOs showcased their company's motto on stage this week, too during Microsoft CEO Satya Nadella's talk on Monday and on Sundar Pichai's talk on Tuesday.Nadella showed off Microsoft's new-ish mission, adopted shortly after he became CEO: “Empower every person and every organization on the planet to achieve more.” (It's original mission was to “Put a computer on every desk and in every home.” And it pretty much accomplished that.Google's official mission is still “To organize the world's information and make it universally accessible and useful.” But given the range of products Google has these days well beyond search, Pichai showed this motto on stage to developers: “Building a more helpful Google for everyone.”There comes a point when, instead of looking like opposites, rivals look like a mirrored image.