Hardy to Ramanujan: What they (referring to Euler and Jacobi) had in common, what I see in you, is a love of form. It's all through your notebooks. Let me ask you something. Why do you do it, any of this? Ramanujan to Hardy: Because I have to. I see it. Hardy to Ramanujan: Like Euler. Form for its own sake. An art unto itself.

The Man Who Knew Infinity.