A man walks into a diner and sits down. There's a new waitress working that he's never seen before.
When she comes to his table to take his order, he says "Just a cup of coffee please." A few minutes later
the waitress brings the man his coffee and heads back to the kitchen. A short while later, the man
notices that there is a fly in his coffee and calls the waitress back. He asks her nicely to bring him
another cup. The waitress brings the man's cup of coffee back to the kitchen and returns a few moments
later. "Here you are, I poured you a new cup of coffee, no fly this time" she says and hands him the cup.
The waitress turns around and starts to head back to the kitchen. She only takes a few steps before
she hears the man shout out "Hey, this is the same cup of coffee, all you did was remove the fly!"
Assuming the coffee was still hot and that the coffee machine is not in plain sight, how did the man
know it was the same cup of coffee?
Do you have a suggestion
for this puzzle (e.g. something that should
be mentioned/clarified in the question or solution, bug, typo, etc.)?