Chelle asked what a "standing wool rug" was so I wanted to post a picture. This one is in process and is made from a variety of wool that is torn or cut to 1/2" strips. Those strips are then rolled and secured to form the mat. I use a long thin needle and thin crochet cotton to sew it together. I sew through the center of the strips to secure it to the "base" and you don't see the threads at all. If you want I can post pictures of how I sew them together.
There are a variety of ways to create different looks, including beading (small rolls), and shirring (folding the strip on the row). This is an old pre-1850's technique (before rug hooking was popular) and creates a plush mat that is sturdy and great as a chair pad or hot plate mat. You can play and create as you go...no patterns! You can use a combination of wools from thick blanket weight to thin and thready. Great for scraps!