Boeing 7J7

[DWG]

That's unfortunate. The 3x3 works and gives fault-tolerance, but the any-4 is a lot more tolerant of damage or malfunction.

And when we did do 3x3 for 757RT (=777 tech demonstrator), they didn't value having a different design team for each of the 3 different processor types in each lane, so we went to single design for 777 itself. OTOH the theoretically design teams apparently converged on identical designs because of the single set of requirements and largely common architecture, so there wasn't much actual redundancy in it.