Hi, 

From: "Tom Sawyer" <transami / transami.net>
>
> bill can you tell where mine is failing? it passes david's tests plus
> the one avi's missed --which your test dosn't seem to catch. would like
> to fix mine though if there's a bug.

I tried reducing the dataset size as far as possible and having it
still fail.  It seems to fail on this:

  big_items = [1, 3, 2, 4]
  big_rows = [[ 2 ], [ 1 ], [ 3 ], [ 4 ]]


Hope this helps,

Bill