Take the title literally! These belts really are designed from the hip: each professional designer was free to do whatever she felt like doing. Maybe you thought designers always do this, but the reality is, a publisher often has their own vision and requirements. The designer is usually required to use a specific color, yarn, or style. Even when there is a lot of design freedom, it can take up to six months to find out if a design is chosen and many more months to see it published.
This is now an invalid link unless you want home improvement advice.