Bubbly eyes. Button noses. Adorable smiles.
Whatever character Pixar Studios creates, there's seldom any other reaction than to wish the toy/monster/robot onscreen was real, just so you could hug it to death. But those adorable animations don't instantly leap from their designers' brains into our hearts. The cuddly creatures come from a source: the mind of an in-house mathematician.
One of those geniuses is Tony DeRose, a senior scientist and lead of the research group at Pixar Animation Studios. He helped shaped the Oscar-winning short Geri's Game and describes the design process as making "pretty complicated shapes" rendered easily onto a computer.
A lot of Pixar characters involve complicated shapes that DeRose recreate from simple geometric formulas — and sometimes the answer lies in a real-world "test character." For the character of Geri, an artist physically sculpted a model of an old man's hand that DeRose then mapped out for the computer. That shape was then broken down into shapes easy enough for any high school geometry textbook, which are eventually put together to form the characters that you love.