13 decks of cards have been mixed. What is the minimum number of cards that must be taken out from the above-mixed cards to guarantee at least one 'four of a kind?

I have an eye but still cannot see.

Who am I?

Can you find the hidden animal in the picture below?

Can you find out the total number of triangles in the given figure?

There are three boxes of different sizes with three cupcakes inside each of the boxes in Christina's kitchen. At night her daughter wakes up and goes to the kitchen. She opens a box and eats all three cakes.

But in the morning Christina finds out that each box still had three cupcakes. How?

What goes up but never comes down?

Look at this sequence from top to bottom. What is the next number in the sequence?
1
11
21
1211
111221
312211

A father's child, a mother's child, yet no one's son.

Who am I?

Can you find the missing piece of the Porsche?

There are forty elephants and they have forty-fore heads. How can this be possible?