3D Celtic knot curled round to form a bracelet, which ends up as quite a nice design. This is a knot with loop dimensions 20 x 3 x 3 and generated with seed 2 using the Knot application.
The inside diameter (the bit you have to get your hand through!) is 5.5cm, so not very large. There's some flexibility, but not much. If you want me to generate a larger version just send me a message and I'd be happy to.
Note this appears to be pushing the limit of what the printer can handle in terms of thread thickness, so some loops may not be fully formed (there were just a couple missing in my print).