The value of each hue should not be duplicated in another ring. Transparent Magenta and Transparent Green. They will make your darkest black neutral mixing color. These are combinations of the six primary and secondary colors that will make a neutral gray.
Shadows can be warm, cool or neutral.
Morning shadows are cool. The darkest shadow color at high noon sunny day is a mix of Quinacridone Magenta and Thalo Green . Warm Cadmium Red Opaque and cool Transparent Thalo Blue are the third major complementary pigment sets to make a neutral dark black transparent combination color for shading Red or Cyan. Each of the 10 columns represent one concentric ring around you. The colors are less intense to any discriminating eye.