https://play.podtrac.com/npr-510313/edge1.pod.npr.org/anon.npr-podcasts/podcast/npr/hibt/2016/09/20160909_hibt_podcastspanx-8139c4f0-9ac2-4b7a-8fb2-c1efa1f2051f.mp3At 27, Sara Blakely was selling fax machines and desperate to reinvent her life. So she came up with Spanx — hosiery that eliminates panty lines — and set to work building her business.