Step 3: Now, it’s time to attach your rope to yarn! Take the materials for your largest rainbow curve (64 cm of rope and 15 yards of yarn). Leave 2 cm from the end of your rope and attach your yarn with an overhand knot. Leave the tail facing back toward the rope length. Step 8: Working from the back of your piece, use your small curved needle and cotton thread to sew every rainbow curve to its neighbor. They should be as close as can be to one another. (Note: If you don’t have a curved needle, a regular one will work too.) Step 10: If you wish, sew a small split ring at the back of your rainbow to hang. Check out more of mbg’s Craft Week how-to’s here.