This is more of a technique than a pattern, and could be adapted to other strap-shaped items. The magic chain in embroidery is a stitch where the links of the chain alternate colors. It is much easier than it looks and I wondered if it could be done in crochet as well - it can! The idea is simple: tie a slip knot with two lengths of yarn together. Chain, yarning over with only one strand at a time and alternating between the yarns. It would be good for fun tassels or perhaps a drawstring - made with something sturdy (t-shirt yarn?) it could be a shoulder strap.