I'm finally getting back to my goal to learn tapestry techniques in 2010.
This is the joining system that says “tapestry” to me. Both colors go around the same warp making a very durable weaving. The finished piece can be hung horizontal or vertical without any sagging or bagging. It is slower to weave since you have to keep all the colors in the same row or they won’t interlock, so you’re always picking up the next butterfly and moving across, unlike some of the other methods where you can take one color and weave just that section because it doesn’t lock with the color next to it.
I did notice that if you made a straight vertical line, where both colors twined around the same warp, because two wefts came together, it would start to bulk up on that warp. So I guess the trick is to not go around the same warp to many times or use a different method of joining.
In my little double square tapestry I was fairly happy with the way it turned out, changing from two wefts to three and back again usually worked out the first time, but sometimes I had to remove or add a half a row to make the weft fall the right order with the raised and lowered warp.