DescriptionAufbau Principle 3D (232 States).svg	The state space of a 3D potential wel with the first 232 states shown. You can see the increasing approximation to a sphere.
Date	5 August 2007 (upload date)
Source	self-made   This W3C-unspecified vector image was created with Inkscape .
Author	Inductiveload
Permission (Reusing this file)	Public domainPublic domainfalsefalse I, the copyright holder of this work, release this work into the public domain. This applies worldwide. In some countries this may not be legally possible; if so: I grant anyone the right to use this work for any purpose, without any conditions, unless such conditions are required by law.

Mathematica Code

Require the following module:

<< Graphics`Polyhedra`

a = Table[{x, y, z}, {x, 1, 10}, {y, 1, 10}, {z, 1, 10}];
a = Flatten[a, 2];
a = Select[
      a,
      #[[1]]^2 + #[[2]]^2 + #[[3]]^2 < 70 &];

Show[
  Table[
    Polyhedron[Cube, a[[n]], 0.3],
    {n, 0, Length[a]}],
  ViewPoint -> {3.5, 3, 1},
  Shading -> False,
  PlotRange -> {{0, 10}, {0, 10}, {0, 10}},
  Axes -> True
  ]