fB Frequenza moto asse verticale.

t = 0 (slider from 0 to 3.141592653589793, step 0.01)
fA = 1
fB = 8 (slider from 0.25 to 16, step 0.25)
a: 25.0 * abs(cos(t))
b: 4.0 * abs(cos(fB * t))
c: x^(2.0) / a + y^(2.0) / b = 1.0