Angles on Christmas Tree in Puzzle!

Four angels sat on the Christmas tree amidst other ornaments. Two had blue halos and two - yellow. However, none of them could see above his head.

Angel A sat on the top branch and could see the angels B and C, who sat below him. Angel B, could see angel C who sat on the lower branch. And angel D stood at the base of the tree obscured from view by a thicket of branches, so no one could see him and he could not see anyone either.

Which one of them could be the first to guess the color of his halo and speak it out loud for all other angels to hear?

THESE angels have maximum chance of correct guess!


Similar Puzzle 

Logical Angels on Christmas Tree

How their logical skills are challenged?

Case 1 :

The angel A observes that the aureoles of B and C are of the same color. Then, A can be sure that the color of own aureoles must be other than that of B and C.

So, A will be the first to guess the correct color in case he observes 2 same colored aureoles B and C.

Case 2 :

The angle D notices that the color of aureoles of B and C are different. Now, A has to remain silent. The silence of A suggests B that the color of aureole of B must be different than the C.

So, in that case, B will be the first one to guess correct color of own aureole.

However, C has no chance to guess the color of own aureole unless, A or B reveals color of own aureole. And D has absolutely no chance of correct guessing the color of own aureole.

The Greek Philosophers

One day three Greek philosophers settled under the shade of an olive tree, opened a bottle of Retsina, and began a lengthy discussion of the Fundamental Ontological Question: Why does anything exist?

After a while, they began to ramble. Then, one by one, they fell asleep.
 
While the men slept, three owls, one above each philosopher, completed their digestive process, dropped a present on each philosopher's forehead, the flew off with a noisy "hoot." Perhaps the hoot awakened the philosophers.

As soon as they looked at each other, all three began, simultaneously, to laugh.

Then, one of them abruptly stopped laughing. Why?

Interesting reason behind it! 

Source 

Theory Of The Smartest Philosopher

What's the story behind? 

The one who stopped laughing was the smartest one among! Read how he was the smartest.

We need to think from the smartest Philosopher's point of view. Let's name 2 other Philosophers as A & B.

Now here is what the smartest Philosopher would think.

"If I had nothing on my head then A & B must have been laughing after looking each other's head. And at least one of them is smart enough to realize that the other is laughing only after looking at him. That means A (or B) would have realized that the some thing is on his head too as B (or A) is laughing after looking him (not me if I had nothing on my head). Hence one of them would have stopped laughing. Since they are not stopping to laugh, I too must have something on my head."

Hence the smartest Philosopher stopped laughing after realizing that the fact.

  
A brilliant puzzle based on the similar logic is here!