That blog isn't very authoritative, and doesn't go into any detail at all.

> I'd imagine every computer relies on redundant stick/pedal encoders, which is how a 12-way notion appeared.

That's disingenuous at best. The lug nuts on my car aren't 20x redundant... if you randomly loosen four, catastrophic failure is possible.

There's several subsystems that have backup functionality or piloting fallback available incase of subsystem failure, and subsystems have internal 2-weay or 3-way redundancy/voting. See eg https://aviation.stackexchange.com/questions/15234/how-does-...