Figure 9. G1, G2, G3 are digital one-dimensional spheres. G4, G5, G6 are digital two-dimensional spheres. G7 is a digital three-dimensional sphere

From

Graph Theoretical Models of Closed n-Dimensional Manifolds: Digital Models of a Moebius Strip, a Projective Plane a Klein Bottle and n-Dimensional Spheres

Alexander V. Evako

Applied Mathematics and Physics. 2017, 5(1), 19-27 doi:10.12691/amp-5-1-3