Since speakers run on AC through the wires, how does one determine which is the 'return' run of the cables on which to use the double run?You build a servo circuit which senses polarity and physically 'flips' the cable around, using super fast relays... :-)
But then who's to say what's the real (?!) "direction"... As though there is something like that... Well. most people would consider the "return" as whatever is connected to the common circuit ground, but even that is not true for certain amps (bridged, some monoblocks or transformer-coupled)...
I follow then rule of symmetry and the KISS concept. To really keep it simple there is nothing better than geometrical balance. It's the best I know AND it's simple alright...