The national flag of Nepal is the world's only non-quadrilateral flag that acts as both the state flag and civil flag of a sovereign nation. The flag is a simplified combination of two single pennons (or pennants), known as a double-pennon.
Its crimson red is the symbol of bravery and it also represents the color of the rhododendron, Nepal's national flower, while the blue border is the color of peace. Until 1962, the flag's emblems, the sun and the crescent moon, had human faces, but they were removed to modernize the flag.
The current flag was adopted on 16 December 1962, along with the formation of a new constitutional government. It borrows from the original, traditional design, used throughout the 19th and 20th centuries, and is a combination of the two individual pennons used by rival branches of the ruling dynasty.
According to en.wikipedia