Here's a way I use up all my scraps of yarn from other projects. If you're like me, I don't like to waste anything. Even a small ball of leftover can be used this way. Holding 4 strands of yarn together and using a size P hook (the large blue plastic one), make a chain the width of the rug size you want. This rug is worked in single crochet, turning at the end of each row. Make sure you write down or remember the number of stitches you started with because it's easy to drop a stitch at the end of the row so I periodically check my stitches. When you finish a color, just pick up another ball, attach and continue. I do not use knots, I lay the two strands together for about 12 inches, ends in opposite direction and work the single crochet with 5 strands for those 12 inches. When another ball comes to an end, I repeat and add another color. Working from the width, you can make the rug as long as you want.