What is the meaning of かい and き in Google's Summer Solstice Doodle? I was wondering what the meaning of and is for the Google Summer Solstice Doodle pictured here: !enter image description here I'm guessing it has some relation to summer, but what?

Unfortunately, it is unlikely that these Japanese letters have anything to do with summer.

These are mascots of Kaikai Kiki Co., Ltd., a company run by Takashi Murakami, the artist who painted this Google Doodle. Also note that the same mascots appear in the Winter Solstice Doodle, too.