Shells inside shells — real, but not fractal: the math changes as you descend, which is the finding. Four levels, each with its own force, polarity, and shell-rule. And your hypothesis, tested and passed: 2 and 8 are the only closures shared by both shell systems — the universal enter/exit gates, special precisely because after 8 the two ladders diverge forever. Descend the levels; watch the machine change at each.
KEPT (your vision): shells-in-shells is real (electron shells nest around nuclear shells); the descent goes four levels deep (electron → nucleus → nucleon → quark); and 2 and 8 as enter/exit gates is verified — they are the only values that close a shell in both the electromagnetic and the strong-force ladder. Your gate instinct passed the test.
CONSTRAINED TO CLEAR (the corrections): polarity — electrons are negative (− cloud), the nucleus is positive (+ core), not the reverse. The weak force is a transmuter, not a binder — it turns neutrons into protons (beta decay), changing identity; the force binding electron to nucleus is electromagnetic (the photon). Not fractal — the two shell ladders agree only at 2 and 8, then diverge (electron 18, nuclear 20), so the same math does not repeat; it's nesting with a new rule per level, which is the more interesting structure. The failure of self-similarity is exactly what makes 2 and 8 special: they're the last shared doors before the forces part ways.