Why knot theory should interest a writer of YA fiction is probably unanswerable, but Ken Millet, a professor of mathematics at the University of California, Santa Barbara, has this to say about asking questions:

As I look at the history of mathematics, there are many problems we are only beginning to know how to ask, but we don’t yet have the intellectual framework or tools to answer. The challenge often is to figure out the questions where you can actually make progress. That’s a real art form that successful mathematicians know how to do. We learn how to ask questions for which we currently have a hope of answering. We can work on impossible questions forever and not get anywhere—the art is to ask those questions that we can possibly answer.

Maybe only children get to ask the unanswerable questions, like where do we go when we die; the rest of us have to make do with doughnuts – or is that coffee cups?