p:0..1
H(p) = a*p**3 + b*p**2 + c*p**1 + d
    I would recommend corners like:
        H(0) = Hmin
        H'(0) = 0
        H(1) = Hmax
        H'(1) = 0
    to get a similar "s" shape to 3*x**2 - 2*x**3, but scaled so the output go from the min to the max you want
S(p) = e*p**3 + f*p**2 + g*p**1 + h
    S(...) = Smin, 0, Smax, 0
V(p) = j*p**3 + k*p**2 + m*p**1 + n
    V(...) = Vmin, 0, Vmax, 0