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

How many triangles can you find in this given picture?

In front of you, there are 9 coins. They all look absolutely identical, but one of the coins is fake. However, you know that the fake coin is lighter than the rest, and in front of you is a balance scale. What is the least number of weightings you can use to find the counterfeit coin?

The more it dries, the wetter it becomes. Can you tell what it is?

Three brothers Jacob, John, and James live in Mexico City. The product of the ages of these brothers is 175. Jacob and John are twins. How old is James?

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

Do you know of a place where the wind blows south and then suddenly shifts direction towards the north?

On a bright sunny day, two fathers took their son fishing in the lake. Each man and son were able to catch one fish. When they returned to their camp, there were only three fishes in the basket. What happened?

PS: None of the fish were eaten, lost, or thrown back.

Can you find the 09 errors in the picture below?

The more of this there is, the less you see. What is it?