han at the  top of the function or at the top of the file.</li>
  <li><strong>Don't reuse same name in inner scope</strong>: Declaring a variable in inner scope with same name as a variable in outer scope will cause inner use of name to "shadow" the outer definition. Not only is this confusing, it often leads to difficult bugs.</li>
  <li><strong>No global variables:</strong> Do not declare variables at global scope. When there is information to be shared across function calls, it should flow into and out v