Flattened Electron Subshell Pyramids

                                                                                                                        1s

                                                                                                                        2s

                                                                                                                        2p 3s

                                                                                                                        3p 4s

                                                                                                                        3d 4p 5s

                                                                                                                        4d 5p 6s

                                                                                                                        4f 5d 6p 7s

                                                                                                                        5f 6d 7p 8s