Suppose you have five matches. How can you form the number sixteen with them?

Close one of your two eyes. Move your head close to the monitor and watch concentratedly to the left circle if you closed your left eye. You should look to the right circle if you closed your right eye. Keep watching and move your head slowly backwards while checking the other circle. What happens? And how is that possible?

You're travelling to some village. At some point there is a fork in the road. You could go two ways but only one of them leads to the village. Lucky for you there are two men standing next to the fork. But unfortunately one of them always lies and one always speaks the truth and you do not know who is who. Since the men do not really like to help you, you are allowed to ask one of them only one question. Which question should you ask?