While on a camping trip, Holmes wakes Watson in the middle of the night and asks “Watson, what can you deduce from looking at the sky?”

“Well,” says Watson, “I can see the North Star, so I know we’re in the Northern Hemisphere. I see Orion, so I know it’s not summer. And that line of clouds approaching tells me that the temperature is dropping.”

“What can YOU deduce from looking at the sky, Holmes?” asks Watson.

“That someone has stolen our tent,” answers Holmes.