I come in different shapes and sizes.
Parts of me are curved, other parts are straight.
You can put me anywhere you like,
but there is only one right place for me.
What am I?

What can go through glass without breaking it?

If I remove one from eleven it becomes Ten and if I remove one from nine also becomes Ten. How?

A wooden log balances equally on the scales when weighed with three-quarters of a pound and three-quarters of a wooden log.

Can you calculate the weight of the entire wooden log?

The peacock is a bird that does not lay eggs. How do they get baby peacocks?

Can you decipher these quotes by Albert Einstein?
Blf xzm mvevi hloev z kilyovn lm gsv ovevo lm dsrxs rg dzh xivzgvw.

I’m tall when I’m young, and I’m short when I’m old. What am I?

The first box has two white balls. The second box has two black balls. The third box has a white and a black ball.

Boxes are labeled but all labels are wrong!

You are allowed to open one box, pick one ball at random, see its colour and put it back into the box, without seeing the colour of the other ball.

How many such operations are necessary to correctly label the boxes?

Why did the Girl throw the butter out of the window?

It comprises roots which nobody sees,
Much taller than those trees,
Up and up it goes,
Still it never grows?