Bernie Wojcicki was an Australian whip maker that made several thousand whips over his life time. Unfortunately I never got the chance to correspond with him as he died in 2016, a few months before I became interested in the craft. He did a series of videos over the last 10 years or so of his life and they are available on his YouTube channel, Bernie46
If you are at all interested in this art you should watch his videos.
This transition is buried in a video he made showing how to do a 16 plait diamond braid for the handle of a bullwhip and this is how he transitioned from the diamond plait to the herringbone plait for the thong.
This is the starting position-the next strand to be worked is the upper right-hand strand (silver.)
the silver strand is pulled around behind the piece and plaited U1, O1, U1,O1, U1, O3
This is repeated on the right hand side, bringing the uppermost left-hand strand behind and U1, O1, U1, O1, U1, O3
The nest upper right-hand strand is brought around behind and U1, O1, U1, O5
and then repeated with the upper left hand strand
The next upper right-hand strand is brought around behind and then U1 O1, U2, O4
mirrored by the upper left-hand strand
Now the herringbone is established and you continue on with and under 4, over 4 pattern.