Back when I was a kid (10 or so) I had this idea as I was being dragged about the mall for a foldable three-legged chair for tired husbands/brothers to carry on shopping trips. It would be a lightweight foot-high contraption that would fold into a package that could be readily secured to the body with velcro or the like. Something one could just grab and unfold in a few seconds to catch a few moments of respite as the fairer sex shopped one to death.