The inscribed square problem (summary here) is currently open:
Does every Jordan curve admit an inscribed square?
(It is not required that the vertices of the square appear along the curve in any particular order)
I failed to come up with a curve that needs the precision about the order of the vertices. Is there a trivial example? Or is it that we simply do not care?

Let me preface this with the fact that I am unfamiliar with this problem or attempts at proving/disproving the conjecture.
I can't include a picture in a comment so I post this here...
Here's an attempt at drawing a curve such that you can't have a square appear along the perimeter with its vertices "in order". I can't see any other squares that match up with my curve, but then again maybe I missed something.
Thanks for pointing out this interesting conjecture. :)