I’d been following instructions to take stand 2 and put it between 3 and 4 etc, and I could execute the steps but not understand what was happening.
But this finally clicked for me, hope it helps others. (1) Twist the two center stands. (2) Twist the two outer stands, but (3) lay them down overlapping the center two, so the new center stands are one from the first twist and one from the second twist.
Oh cool. I’ve been trying to generalize the n-strand braiding algorithm, so appreciate the geeking out.
My favorite thing about 4 strand plaiting is that if have 2 of the same colour on one side you end up with checkers and if have 2 on either side you get a spiral. Make a marble rye!