Designers can type in descriptors such as "sharpness" or "acceleration" (which refers to a curve's severity) and watch as the lines of a sports car or tea kettle automatically undulate.
Gravity takes over when you perform most exercises, like a dumbbell curl or a kettle bell swing, giving the body a chance to relax, says Rowdy Yates, a certified personal trainer and fitness manager at Crunch gym in New York City.