Why Aeroplane windows are round?

Nine marbles are arranged in the image below. Can you slide two marbles to form a square?

One night, Louis and Adam were sitting together. Adam was watching a movie while his wife Louis was reading a mystery book. Suddenly the power went out and Adam decided to go to bed, but strangely Louis kept on reading. There was no artificial light around, so Louis kept on reading. How come?

We know that the number 7 is the prime followed by a cube. Which next number is also a prime followed by a cube?

Who is that with a neck and no head, two arms and no hands? What is it?

By moving exactly three matchsticks can you make the below equation true.It can be solved by 3 ways.

What occurs twice in a week, once in a year but never in a day?

Which is heavier: a ton of bricks or a ton of feathers?

There's a day, that comes around once a year.
To celebrate the man, you hold dear.
He gave you life, love and will pick you up if you fall.
When it comes to guys like him, He's the best of all.
Who is he?

An octopus has 8 legs. A hippogriff has 6 legs and 2 pairs of wings. A sphinx has 6 legs and one pair of wings. Now we have all 3 kinds and a total of 18 insects in a cage. We have a total of 118 legs and 20 pairs of wings. How many insects do we have of each kind?