Always Coming But Never Arrives



What is always coming but never arrives?

Ah! Click here to read the solution.



The Box And The Valuable Object



You want to send a valuable object to a friend.

You have a box which is more than large enough to contain the object.

You have several locks with keys.

The box has a locking ring which is more than large enough to have a lock attached.

But your friend does not have the key to any lock that you have.

Please note that you cannot send a key in an unlocked box, since it might be copied.

How is this done?

Ah! Click here to read the solution.