I thought you might like to see one of my rag rugs. This is entirely recycled material, 3-1/2 pairs of my husband's jeans and about 1/4 of an old flannel twin sheet. The backing is a denim tote bag I made to schlep my sewing machine, which hasn't been used in many years so I unpicked it. The rug is approx 20 x 30.
They are neither complex or difficult to make and there are many ways to do it. THIS one was made by cutting the dead jeans into 3" squares and folding them in half diagonally to make a triangle shape. Discard seams etc. You don't have to use denim. I do because what else are you going to do with ripped and stained jeans? You can do this with old tee shirts using at least two squares, or shirts which you can pick up for pennies at thrift shops. If you are using shirts the material is thinner so use more squares, this is your 'pile'.
Decide what size you want your rug to be, bearing in mind that the bigger the rug the heavier it will be to lift out of the washer when wet. You will need a sturdy piece of backing material, you can get 60"+ wide denim at Walmart very inexpensively in the flatfold fabric section. I usually buy new for the backing since that is what holds the whole shebang together.
Fold the backing so it is doubled in thickness and stitch about 1/2" in from the edge all around the perimeter. Don't worry about the raw edges. Next draw lines with a ballpoint as a sewing guide. 1-1/2" is the maximum spacing, the pile feels lumpy to me if you go further apart than that. My method is to take the length of the mat and divide it by 1.5". If it comes out to an odd number move the lines closer, the mat will be denser.
It is easiest to stitch the rows by stitching the center row first, then the rows on either side, working evenly to the ends of your rug. You will have less bulk to wodge under the sewing machine arm as you progress from the middle to the edges.
Now start stitching! Place your folded fabric triangle with the folded edge on the edge of the backing and the point on the guide line pointing at you. Stitch about 1/2 way down the triangle and place the folded edge of the next triangle on top in the same way, stitch, place, stitch until your row is done. It comes out to about one square folded into triangle per lineal inch in the row.
Neatness does not count.
I always start the stitching and after about 1/4" reverse and backstitch over at the beginning and end of every row. Makes things stronger.
On THIS mat I changed the direction of the triangles on each row. I don't always do it that way, do whatever turns you on. When I was done with this one the mat felt a bit lumpy, so I stitched strips of flannel sheet (4 layers) between the rows.
Next to the washer, it will fray like crazy, might want to take it to the laundromat. Then the dryer to fluff. Clean the lint trap every ten minutes or so. It WILL clog up fast. This mat will outlive me. As a bedside or bath mat they more or less last for ever. As a front door mat inside, they get to looking grungy in my house after about ten years. I wash them frequently and will use a package of RIT dye as the whim takes me.