This post (particularly the illustration) explained a lot to me as a new weaver. Like why there are four holes on each treadle, even though there is a one-to-one correspondence between treadles and shafts.
After I finished weaving my twill scarf, I had leftover warp, so I did some sampling. I love how the different materials interacted combined with the different treadlings. What pleases me the most is how much of it resembles worn denim.