The warp alternates 2 threading blocks with 3 thread colors. This is a two shuttle weave and each block of the 2-block treadling uses two colors in the weft, and the color combination changes with each block change. All 3 of the warp colors are used in the weft in this order: Purple & Red (purple for 1st and last pic) / Green & Purple (green used for 1st and last pic) / Red & Green (red used for 1st and last pic).
This alternating color arrangement gives a two-colored stripe block that changes with each block.
If you have more than 4 shafts, the original directions recommend using a left and right border of plain weave, threaded on shafts 5 and 6.
I really like the way this looks, but it was a bit of a pain to weave (using 2 shuttles and a color change at every block) and I will probably not use this color/weave arrangement again.
