I came across an old 2005 article in the New York Times about Mike Leach. It's very interesting and is 9 pages long so it's very detailed about who he is, the quarterbacks in his system, and other important details about his coaching style and other aspects.
If this has been posted before I apologize. I searched the site using the search engine and nothing came up. If you haven't ever read this, do because it details Leach and includes the sand pit in the read and it was a great read to learn more about him.