In the 6th Century BCE, the Greek Pythagoreans believed that the number 3 represented Harmony since 1 meant Unity, and 2 meant Disorder. Add the two together and you reach a harmonious conclusion.
Explanation:
The number three is considered lucky for a number of reasons. First, there's the fact that a man and a woman — a unit of two — can become a unit of three with the creation of a child, giving the number three a bit of magic all around the world. In Christianity, there's the Father, Son and Holy Spirit; Islam has its three main holy sites. This magic associated with the number three has given rise to sayings like "third time lucky" and "third time's a charm," both of which suggest that two failures are sure to be followed by success on the third attempt.
This metaphor basically means that if certain problems cannot be changed, look outside the box when you try to solve them. Try to solve the atmosphere or try to solve everything around the problem. If the problem can't be solved change the situation around the problem and eventually your solutions will be solved