Twisting 6 feet of solid 14 gauge wire?
Try an electric drill.  Put the two ends of the wire into the drill chuck; fasten the other ends of the wires to something; step back until the wires are taut, then turn on the drill.  As the wires twist and the cable shortens, you'll have to walk forward to where the wires are anchored.

But I'm not sure if this would work with your "90 degrees to each other" requirement.