Re: triple fire plug, etc
Here's my $0.02 worth on the 3 pronged plug: I'm of the opinion that as it applies to our HT engines it is mostly redundant. Electricity like water takes the path of least resistance. With the 3 prong plug the spark will simply jump to the nearest electrode. I doubt our ignition systems put out enough juice or of a long enough duration to be able to sustain a 3 pronged spark. In aircraft engines it's a different story. Much more powerful ignition systems combined with the need for added safety in case an electrode fails for instance. Planes typically have double or triple fail-safe systems.
However, there's always exceptions to the rule. When I was a kid I had an old 2 stroke dirt bike with an old ratty engine and on more than one occassion I had a bit of old carbon deposit from the combustion chamber lodge itself in the gap of the plug killing the engine. Had to take the plug out and remove the piece of carbon, put plug back in and continue terrorizing the dunes. With a 3 prong plug, well you get the picture.....
McGyver could fix that with bubble gum.