The colours which ARE on the Olympic flag are Red Blue Green Yellow and Black on a White background.
Any other colours than these are not on the Olympic flag.
Lybia has a green flag
Libya has only green colour on her flag.
The Libya flag is the only country to have a flag with only one color. The flag is solid green. It is green because green is the national color of libya showing their devotion to islam.
Prior to the Arab Spring War in 2011, the national flag of Libya used to have only one color; green. More specifically, it consisted of a simple green field with no other characteristics. Also, many signal flags are just one color. Then, of course, the flag of surrender is but one color; white. Currently, there is no national flag with only one color.
blue and white
The flag of Egypt's colors are: ~Red ~White ~ And Black
Any country's flag represents that country, and should be treated with due respect.
I don't know of any such flag, but the German flag (among others) is gold, red, and black, which in some badly color-corrected pictures might appear to be yellow, orange and black.
The flag for the country of Belarus is red and green in color. The flag also has a red and white ornament design on the staff side of the flag.