Sherlock Holmes and Dr Watson go on a camping trip. After good dinner and a bottle of wine, they retire for the night, and go to sleep.
Some hours later, Holmes wakes up and nudges his faithful friend. "Watson, look up at the sky and tell me what you see."
"I see millions and millions of stars, Holmes" replies Watson.
And what do you deduce that from?
Watson ponders for a minute. 'Well,
Astronomically, it tells me that there are millions of Galaxies and potentially billions of planets.
But what does it tell you Watson?
Holmes is silent for a moment.
Watson, you idiot! he says. Someone has stolen our tent?