Answer:
I turn around once. What is out will not get in. I turn around again. What is in will not get out.
I cannot be bought, cannot be sold, even if I'm sometimes made of gold. What am I?
They come at night without being called and are lost in the day without being stolen. What are they?
I am needed for most animals and hardcover books. What am I?
A man who was outside in the rain without an umbrella or hat didn't get a single hair on his head wet. Why?
I flow from the Homerβs mouth when he sees doughnuts.