This is an easy way to do it.
Worsted weight yarn in at least 4 colors
Crochet hook size H
Cardboard or pillow to pin to
For this strap you will need 4 ropes, each of a different color. You will make them double the length that you want the final strap to be.
If you are unseru about what that length would be, before you start, make a ball of yarn for every single rope you will need, crochet from that ball and do not cut the yarn off the ball until you have made your strap, to make sure you will have the length you want. If you have too much, you simply unravel a bit, you you need some more, you simply make a little bit more.
If you need to learn how to make our ropes, please go here for the original tutorial:
Once you have your ropes made, pin them onto a cardobard or a pillow to be able to comfortably work with them.
To make the strap, proceed as follows:
1- Cross the two center ropes, the one on the left over the one on the right. Now cross rope 4 over rope 3 and rope 2 over rope 1.
2- Repeat step 1.
3- Repeat step 1.
4- Bring the first rope on the left over the one next to it, bring end to the back and through loop that formed, tighten a bit. Bring first rope on the
left over the rope next to it, bring end to the back and through loop, tighten a little. Repeat these steps once more.
Repeat steps 1 to 4, as many times as needed, to form your strap until you have the length of strap you want.