It's a protector.
It sits on a bridge.
One individual can see directly through it, while others wonder what it hides.

What is it?

Find The Next Number In The Sequence

30 10 15 13 0 16 -15 ?

As easy as you can get into me, it is as hard to get out of me.

Do you know what I am?

Two guards were on duty outside a barracks. One faced up the road to watch for anyone approaching from the North. The other looked down the road to see if anyone approached from the South. Suddenly one of them said to the other, "Why are you smiling?"

How did he know his companion was smiling?

You have 10 balls with you. A friend of yours out of nowhere asks you to place those ten balls in five lines such that each of the lines has exactly 4 balls on them. He needs to check your intelligence. Prove him by doing the task.

What always comes into a house through the keyhole?

A sundial has the fewest moving parts of any timepiece. Which has the most?

What is the word or phrase?

Can you divide numbers from 1 to 9 (1 2 3 4 5 6 7 8 9) into two groups so that the sum of the numbers of each group is equal?

Note: 9 cannot be turned over to make it 6.

In two decks of cards, what is the least amount of cards you must take to be *guaranteed* at least one four-of-a-kind?