This was probably not an Ordnance Survey style grid based on a system of mile or kilometre squaring, but a system based on squares identified by letters and numbers.
Lewis Carroll | Donald Trump | Donald Duck | Jerry Lee Lewis | Donald Rumsfeld | Jerry Lewis | Lewis | C. S. Lewis | Carl Lewis | Donald Knuth | John Lewis | Donald Sutherland | Sinclair Lewis | Huey Lewis and the News | Donald Judd | Donald Honig | Michael Lewis | Juliette Lewis | Donald Bradman | Lewis gun | Lewis & Clark College | Lewis Hamilton | Lewis Carroll's | Daniel Day-Lewis | Lennox Lewis | Donald Pleasence | Huey Lewis | Donald Byrd | Stephen Lewis | Ramsey Lewis |