Sara Bixler’s Sweet and Simple Runner project is woven on a rigid-heddle loom using two heddles to get a warp sett (density) of 20 ends per inch. Here’s a YouTube video from WEBS that shows how to warp a rigid-heddle loom with two heddles.
How to Thread Double Heddles with Leslie Ann Bestor
If you like this project and technique, Long Thread Media also offers a couple of online courses (available with a subscription) that you might enjoy:
Double Your Fun: Doubleweave on a Rigid Heddle Loom with Liz Gipson
Creative Weaving: Leno Lace with Sara Bixler