The Logic Off Topic list

Dennis Gunn wrote:
> While I worked in a patent law firm in the 80's I prosecuted and
> successfully obtained a patent for an invention that consisted of no
> more than a piled stone jetty completely encircling a body of water.
> Can you guess what it did?

  Before I pretend to know the answer, I would like to ask what the Grand
Prize is??????    :-))     --Roger