Author: Andreas Lindner

t = 2.35 (slider from 0.1 to 3, step 0.05)
φ = 0 rad (slider from 0 to 6.283185307179586, step 0.017453292519943295)
a = Function(-1 / sqrt(x^(2) + y^(2)), -3, 3, -3, 3)
r = 0.3 (slider from 0 to 5, step 0.1)
B: (t * cos(φ), t * sin(φ), (-1) / t)
b = CurveCartesian(k * cos(φ), k * sin(φ), -1 / sqrt((k * cos(φ))^(2) + (k * sin(φ))^(2)), k, 0.1, 3)
w: (r * t^(2) * cos(φ) / sqrt(t^(4) + 1), r * t^(2) * sin(φ) / sqrt(t^(4) + 1), r / sqrt(t^(4) + 1))
C: B + w
wn: ((-r * cos(φ)) / sqrt(t^(4) + 1), (-r * sin(φ)) / sqrt(t^(4) + 1), r * t^(2) / sqrt(t^(4) + 1))
M: B + wn
d = Segment(B, C)
f = CurveCartesian((t - r / sqrt(t^(4) + 1)) * cos(φ), (t - r / sqrt(t^(4) + 1)) * sin(φ), -1 / t + r * t^(2) / sqrt(t^(4) + 1), t, 0, 6.28319)
c = Sphere(M, r)
Liste1 = Sequence(CurveCartesian[k * cos(α), k * sin(α), -1 / sqrt((k * cos(α))^(2) + (k * sin(α))^(2)), k, 0.1, 3], α, 0*°, 360*°, 30*°)
e = CurveCartesian(cos(t), sin(t), -1 / sqrt(cos(t)^(2) + sin(t)^(2)), t, 0, 6.28319)
Liste2 = Sequence(CurveCartesian[a * cos(t), a * sin(t), -1 / sqrt((a * cos(t))^(2) + (a * sin(t))^(2)), t, 0, 6.28319], a, 0.2, 1, 0.2)