Six glasses are in a row. The first three are filled with milk and the last three are empty. By moving only one glass, can you arrange them so that the full and the empty glasses alternate?

This is a classy optical illusion puzzle. What more you can find except bricks in the image below?

Rearrange the letters in "new door" to make one word.

A professor thinks of two consecutive numbers between 1 and 10.
'A' knows the 1st number and 'B' knows the second number

A: I do not know your number.
B: Nor do I know your number.
A: Now I know.

What are the four solutions for this?

When Jack was six years old he hammered a nail into his favourite tree to mark his height. Ten years later at age sixteen, Jack returned to see how much higher the nail was. If the tree grew by five centimetres each year, how much higher would the nail be?

If you had a pizza with crust thickness 'a' and radius 'z', what's the volume of the pizza?

I can be cracked, made, told, and played. What am I?

Can you convert the number zero(0) into a positive number using just one mathematical operator ?

A man and a dog were going down the street. The man rode, yet walked. What was the dog’s name?

I have holes on the top and bottom. I have holes on my left and on my right. And I have holes in the middle, yet I still hold water. What am I?