Summarize:

To create a more durable rug, you will need to work with two skeins of yarn at the same time. Treat the two strands as one as you make your stitches. Use an adjustable knot called a slip knot. Make 21 chain stitches to provide your rug with a foundation. Work 40 single crochets into this foundational chain.  Make your first single crochet into the second chain stitch away from your hook after you complete the foundational chain. Single crochet 20 times down one side of the chain. Single crochet another 20 times down the other side of the chain. Make the second round by working another single crochet into each of the 40 stitches completed in the previous round.  Increase twice at both the starting and finishing ends of your first round. To make one increase, chain stitch once. To make two increases, simply chain stitch twice. The third round will essentially be the same as the second. Work another series of single crochets into the all of the stitches of the previous round, including the increases, until you travel around the entire perimeter of the piece. For this round, you need to increase three times at both ends. To increase three times, make three chain stitches. For rounds four, five, six, seven, and eight, single crochet once into each of the stitches from the previous row, including the increases.  Increase at both ends for each round. Continue adding an extra increase for each round.  Round four gets four increases. Round five gets five increases. Round six gets six increases. Round seven gets seven increases. Round eight gets eight increases.   Note that if the rug begins to seem too loose or floppy, you can reduce the number of increases you use at the ends of each round. Change colors before making the ninth round. After you do, make another five rounds using the same pattern: single crochet once into each stitch of the previous round.  Continue adding increases at the ends of each round.  Round nine gets nine increases. Round 10 gets 10 increases. Round 11 gets 11 increases. Round 12 gets 12 increases. Round 13 gets 13 increases.   Note that if the rug begins to seem too loose or floppy, you can reduce the number of increases you use at the ends of each round. To change the color, cut the yarn you are currently working with, leaving a tail 3 inches (7.6 cm) long. Slip this end through the back of the next stitch, turn the rug around halfway, and begin single stitching your next round with the new color. Tie the next color onto the crochet hook using a slipknot. When you reach the tail from your previous color after working your way around, weave it into the new color as you make your next stitches. Change colors a third time after finishing round 13. Afterward, make another five rounds by single crocheting into each stitch of the previous rounds, including the increases.  Continue adding increases at the ends of each round.  Round 14 gets 14 increases. Round 15 gets 15 increases. Round 16 gets 16 increases. Round 17 gets 17 increases. Round 18 gets 18 increases.   Note that if the rug begins to seem too loose or floppy, you can reduce the number of increases you use at the ends of each round. Switch your yarn color one final time. Make another six rounds using the same method of single crocheting once into each stitch of the previous rounds.  Continue adding increases at the ends of each round.  Round 19 gets 19 increases. Round 20 gets 20 increases. Round 21 gets 21 increases. Round 22 gets 22 increases. Round 23 gets 23 increases. Round 24 gets 24 increases.   Note that if the rug begins to seem too loose or floppy, you can reduce the number of increases you use at the ends of each round. e last row. Even out the edge by making a slip stitch into each stitch of the final round. Cut the yarn so that a 3 inch (7.6 cm) tail hangs off the edge of the rug. With a loop still on your hook, grab this tail and pull it through the loop, tightening the loop over it. This will create a knot and tie off your project. Use a darning needle to weave the remaining end into the underside of the rug to hide it.
Use two strands of yarn. Tie the two pieces of yarn onto the hook. Chain stitch and single crochet your first round. Single crochet the second round and increase. Single crochet the third round and increase. Repeat this pattern for five more rounds. Change colors before continuing. Change colors after another five rounds. Change colors before completing the final six rounds.  over the last row. Tie off the end.