THEM: i'll give you 1 ball and 1 hat  YOU: no thanks. i'd like 2 books and 1 ball. you can have all the hats.  THEM: nope, 1 book and 1 hat  YOU: no thanks. i'll take the 2 books and you can have everything else.  THEM: 1 ball and a hat  YOU: no. i want 2 books.  THEM: 1 book  YOU: 1 book and 1 ball for me.  THEM: nope, 1 book and a hat  YOU: no, the hats have no value to me. i want the 2 books.  THEM: ok deal.