How is a fly different from a mosquito?

Can you move 2 matchsticks to form four equal sized squares.

The captain of a ship is telling you an interesting story and then poses a question. He says, “I have travelled the oceans far and wide. One time, two of my sailors were standing on opposite sides of the ship. One was looking west and the other one east. And at the same time, they could see each other clearly. Can you tell me how that was possible?”

How will you measure 15 minutes using two hourglasses of 7 minutes and 11 minutes respectively?

Can it be possible to build a house that has all its four walls facing towards the South?

John and Jacob are twin brothers. One of them is a liar whereas the other one is a truth-teller.

I called their home number and one of them picked up.
I asked. 'Does John lie?' The person replied with a yes.

Whom did I talk with, John or Jacob?

A doctor and a boy were fishing. The boy was the doctor’s son, but the doctor was not the boy’s father. Who was the doctor?

If six children and two dogs were under an umbrella, how come none of them got wet?

Can you start the fire using two pieces of wood?

It walks on 4 when its young, walks on 2 when it's older, and walks on 3 when its very old?