Answer:
Whoever makes it, tells it not. Whoever takes it, knows it not. Whoever knows it, wants it not. What is it?
What goes around and around the wood, but never goes into the wood?
Bury deep, Pile on stones, My mind will always Dig up them bones
What looks back but cannot see?
Where do you go in through one hole and come out through two holes at the same time?
What is so fragile that saying its name breaks it?