Take the thick cord and cut off the end and use masking tape to wrap it around the ends. Now wrap tape around the 2 outer loops and end up with 3 cord sections that stack on top of each other nicely.
Hold all 3 sections together like rainbow shape. Now take a pencil and draw a line across all rows at the height you would like your colorful yarn to go to. Start with the inner section and start wrapping your embroidery yarn tightly around the cord. Hold the end of the yarn and cover it by wrapping the yarn around.
When you reach the mark indicating the end, Cut the embroidery yarn and add a needle. Now pull the yarn tightly through the cord twice and cut it flush.
Repeat this process with the other 2 cords in coordinating colors. For the top row, use a bit of cord and tie a knot with a loop. Then weave it into the top of the rainbow for hanging.
Just spread the ends on either side and wrap the embroidery yarn over the ends and the cord and keep going on the other side of the knot. Now combine the 3 rows by stitching and make beautiful rainbow by adding pom poms!