[math-fun] Mildly surprising: The 2-sphere of radius 2

(at the origin) bisects the unit 2-sphere at (1,1,1): Graphics3D[{Sphere[{0, 0, 0}, 2], Sphere[{1, 1, 1}]}, PlotRange -> {{0, 2}, {0, 2}, {0, 2}}] gosper.org/2spheres.png --rwg