Hello, I have such a diagram and want to figure out the equation which produces it:

One can imagine it as a 3-dimentional space with color responces for every S/U/D combination.
I filled S/U/D into a JMP table to fit (some kind of) model but realized immediately, that the response in color code (e.g. 1 for green, 2 for yelow and 3=red) doesn't make much sense.
To my understanding, the equation behind this diagram generates 4x4x3=48 values and colors correspond to certain parts of values. For example, 30% of upper values get red, 25% lower -- green. The rest is yellow.
How then should I represent the responce?
Isn't it too many unknowns for this task?