Half-twist and link -- in a Sestina

     Mobius strip       by Heidi Willamson

     A simple science trick to try at home.
     Half-twist a slip of paper. Link the ends
     to make an ‘O’. Take a pencil, trace a line that loops
     the shape formed by the surface. See
     how the in and out sides merge. The join
     tangles dimensions. There’s no front or back.