How can you leave a room with two legs and return with six legs?

Once upon a time, there was a castle on a square island. The entire island was surrounded by a 14m wide trench. The Romans had wanted to invade the castle and had brought a few wooden planks along with them to facilitate themselves in crossing the moat. The planks were however found to be only 13m long.

The Romans still managed to cross the trench. How did they do it?

Can you divide the below-given shape into four equal and identical pieces?

The more you take me, the more you leave me behind.
Who Am I?

What does the following represent?

N N N N N N N

A A A A A A A

C C C C C C C

The doctor prescribed you to take one pill from the bottle every half an hour. The bottle is now left with only three pills.

How long do you think you have before you run out of pills?

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

In a chess board, the queen piece can move horizontally, vertically and diagonally freely. The picture represents the same.Can you place 8 queens on the board in a manner that none of the queens can attack each other?

Can you solve below mathematical equation?

2^1234 - 2^1233

You are stuck on an island where you have nothing. You find four pieces of paper somewhere on the island. What will be your strategy to escape from the island safely?

PS: No other resource is available to you on the island, neither can you build anything.