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

Three people enter a room and have a green or blue hat placed on their heads. They cannot see their own hat but can see the other hats.
The colour of each hat is purely random. They could all be green, blue, or any combination of green and blue.
They need to guess their own hat colour by writing it on a piece of paper, or they can write 'pass'.
They cannot communicate with each other in any way once the game starts. But they can have a strategy meeting before the game.
If at least one of them guesses correctly they win $10,000 each, but if anyone guesses incorrectly they all get nothing.
What is the best strategy?

There are 2 people near the river and both of them want to get on the other side. The boat can only take one of them. But they got across.
How?

In 1990, a person is 15 years old. In 1995, that same person is 10 years old. How can this be?

I get hot but I never sweat,
I cook food but I am not a chef,
I have a door but you can't enter me,
I have a light but I am not a lamp.
Who am I?

I add 5 to 9 and get 2. The answer is correct, so what am I?

Spot 5 differences in two Christmas tree below:

You walk into a room that contains a match, a kerosene lamp, a candle and a fireplace. What would you light first?

Christina is practising her dance steps along with her friends. In a particular sequence, all of them form a row. At that point, Niharika is standing in the 4th position from either end of the row.
Can you find out how many girls are practising together?

Six glasses are in a row. The first three are filled with milk and the last three are empty. By moving only one glass, can you arrange them so that the full and the empty glasses alternate?