The sun within the lower triangle represents determination and a fierce resolve. The moon in the upper part stands for peace, tranquility, and harmony. Both of these elements stand together representing the hope that Nepal will be as everlasting as these two heavenly bodies.
It is also the only country whose flag design and construction are written into the Constitution. The previous flag of Nepal, prior to 1962, was of similar shape and somewhat more intricate design, and was in use for more than 2,000 years.
Incidentally, The flag of Libya is the only flag containing one color and consists solely of a solid green background. Green is the national color of Libya as well as a symbol of devotion to Islam. Green also represents Libyan President Muammar al Qaddafi's 'Green Revolution' - an intention to turn Libya into a wealthy agricultural nation.