function nested_fun
x = 5;  % All variable used or defined in outer function are available to 
        % all nested functions
z = nestfun1; 
   function y = nestfun1
      zz = nestfun2;
      y = zz + 1;
       function y = nestfun2
           y = x^2; % x has been defined in outermost function
       end
   end
z 
end % end statements are required for all nested functions (including
    % outermost