Δp = 0.47 (slider from -0.5 to 0.5, step 0.01)
I_2(x) = 1 + cos(((2 * π) * (x - Δp)))
I_1(x) = 1 + cos(((2 * π) * x))
a: I_2 = 1 + cos(((2 * π) * (x - Δp)))
I_t(x) = I_1(x) + I_2(x)