For choosing the colors for the MADRIX Standard Color Setup, the Circle of Fifths from music education is being used. Starting with C, this notion describes a circle. Because of that, the relationship of the keys is visible from the arrangement.
Adjacent keys are named 'parallel keys'. The greater the distance between two keys, the less related they are. To support this fact, complementary colors are used in MADRIX.
The outer ring of the circle describes the major keys, the inner ring the minor keys. While colors describe the tonality, the scale of the color is being expressed with the help of the brightness.
By assigning yellow to the tonality C and due to the fact that the colors are assembled clockwise, all other colors emerge. Consequently, Fis gets assigned blue, the complementary color of yellow.
Any other color for the keys between C and Fis arises from the spectrum of colors between yellow and blue of the RGB color model.