"When a branch of mathematics ceases to interest any but the specialists, it is very near its death, or at any rate dangerously close to a paralysis, from which it can be rescued only by being plunged back into the vivifying source of the science."

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Even in the obscure vast history of a planet the time it takes to make a forest counts. It takes a while. And not every planet can do it; it is no common effect, that tangling of the sun's first cool light in the shadow and complexity of innumberable wind-stirred branches.

— Ursula K. Le Guin