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Figure 3 - The Riemann Sphere in GeoGebra

Given a complex number z_1=1+i, the PRiemannz tool plots the spherical point RS(z1) whose image by the stereographic projection, in consideration, is exactly z_1. The point in the sphere is given, as expected, by Intersect[Segment[(0, 0, 1), z_1], Sphere[(0, 0, 1), 1], 2].