How light propagates around our 4D Spherical Universe

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(Rendered in 2160p but editor/YouT) Suddenly, a Supernova emits a bright flash of light -- which expands its way around the universe.   Normally this would be a expanding 3D sphere, but here its scaled down to 2D ring of light. expanding spatially while moving "upward" away from the 4D origin point as time progresses forward.  How long before we see ourselves? 

 (The answer is a Noble Prize for the team that reconciles Dark Flow with cosmological lensing discovered in the Planck Satellite data.)