The design for the Northeastern Quarter of the Earth is based upon designs in tribute to Whitney Smith. The Northwestern Quarter is the quarter is where the Northern and Eastern Hemispheres overlap. The dart or chevron to the fly design, as proposed for the flag of Guyana, was Smith's concept for a national flag.
However the colour scheme stems from ancient Chinese Cosmology. Reason being, black is associated with the North and blue is associated with the East. Yellow is also included, since it acts as the reference point from the center.
More recently these colours have been popularized in Japanese pop culture, with the black turtle of the North and blue dragon tiger of the South. Furthermore, nearly the entire world under the age of 30 has some notion of these concepts due to the rise of Anime and Pokemon.