My dad learned this trick from a stereo installer when he worked at a Honda dealership. If you use similarly-sized wires, the resulting twist pattern is very uniform and professional-looking. Cut off a bunch of pieces of wire, then stuff all of the ends into a the drill chuck and clamp it down. Start the drill turning, and use your other hand to keep tension on the wires.
In this case, I made a wiring harness with a stereo audio cable and two power conductors.