Mary and Tom have a rather unusual relationship and live in an unfortunate location, but they have been corresponding for a long time, and Tom really wants to send Mary a ring. He paid quite a lot for it, so he doesn’t want to risk it being stolen.
He thinks to himself that he could just put a lock on the package, but then he remembers that Mary would have no way to open it.
What if he sent her the key first? No, that wouldn’t work either. It would be stolen too!
It seems like quite a conundrum until he has a sudden idea. Any guesses?
Tom puts a lock on the package, writes a note on the outside and sends it away to Mary:
Please add your own lock and send this package back to me.
Mary is a little confused, but she does as she is asked. When Tom gets the package back, he removes his own lock and leaves Mary’s on the package. He puts it back in the mail and it arrives safely in Mary’s hands.
I wonder what she’ll send back!