β = 0.59 (slider from 0 to 0.99, step 0.01)
x_1': y = (β * x)
x_0': y = (1 / β * x)
A = Intersect(x_0', x_1')
B, C = Intersect(c, x_1')
distanzaCA = Distance(C, A)
TestoCA: "\overline{" + (Name[C]) + (Name[A]) + "} \, = \, " + distanzaCA
D = Point(x_0')
e = Line(D, xAxis)
x_0'' = Mirror(x_0', e)
distanzaDA = Distance(D, A)
TestoDA: Name[D] + (Name[A]) + " = " + distanzaDA
f: (2 * distanzaDA / distanzaCA)
E = Intersect(x_0'', yAxis)
distanzaEA = Distance(E, A)
TestoEA: Name[E] + (Name[A]) + " = " + distanzaEA
testo1: "EFFETTO GEMELLI

osservatore a Terra:    Δt = " + distanzaEA + "

astronave:                      Δt' = " + f + ""
u = Vector(A, D)
v = Vector(D, E)