It starts with one teacher asking a group of student to make one sentence that has the same meaning with “Billy owned a watch but not anymore, he lost it”. Jenny and Jack come out with different answers.

Jenny: Billy had had a watch.
Jack: Billy had a watch.

The teacher liked Jenny's answer.

Below is the sentence being used in the previous blog entry. Thanks to Jordan, this time it comes with single quotes on it. :)

Jenny, where Jack had had ‘had’, had had ‘had had’; ‘had had’ had had the teacher’s approval.

There you go, grammatically correct sentence.