“…If B 11 = B 22 (⇔ E 1 = E 2 ), then in addition, the lines θ = π/4 and θ = 3π/4 are symmetry axes of the curve c R = c R (θ) in the interval [0, π/2] and [π/2, π], respectively, by the second of (35). With this fact now we can understand why the curves c R = c R (θ) in the figures 14, 15, 18, 19 in [6] have the symmetry axis θ = π/2 in the interval [0, π], while the curves c R = c R (θ) in the figures 16, 17, 20, 21 in [6] have the symmetry axis θ = π/4 in the interval [0, π/2] and the symmetry axis θ = 3π/4 in the interval [π/2, π], in addition.…”