How does a hula hoop master gravity? Mathematicians prove that shape matters

Hula hooping is so commonplace that we may overlook some interesting questions it raises: ‘What keeps a hula hoop up against gravity?’ and ‘Are some body types better for hula hooping than others?’ A team of mathematicians explored and answered these questions with findings that also point to new ways to better harness energy and improve robotic positioners.
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