A novel cluster-shell model is developed by mapping the geometric and algebraic properties of the Rubik's cube to a crystal cluster with three shells (〈100〉, 〈110〉 and 〈111〉), whose coordination numbers are 6, 12, and 8, and radii are 1, √2, and √3, respectively. Expanding the radius from √3 to 2√3 results in a 5×5×5 cube containing six shells: 〈200〉, 〈210〉, 〈211〉, 〈220〉, 〈221〉, and 〈222〉. Further expansion to 3√3 yields a 7×7×7 cube with ten shells: 〈300〉 to 〈333〉. This approach provides both a clear physical picture and a point-group symmetry perspective of the coordination numbers characterized by the RCS model.