Answer:
It holds most knowledge that has ever been said. But is not the brain, is not the head. To feathers and their masters, it's both bane and boonΒ One empty, and one full.
Long legs, crooked thighs, little head, and no eyes.
What has two legs but doesn't walk?
Face with a tree, skin like the sea. A great beast I am. Yet vermin frightens me.
Who spends the day at the window, goes to the table for meals. And hides at night?
You use it between your head and your toes, the more it works the thinner it grows.