%List2
%2
declare fun {Fib1 N}
       if N==0 then 0 elseif N==1 then 1 else {Fib1 N-1}+{Fib1 N-2} end end

{Show {Fib1 37}}
%approx 10 secs

declare fun {Fib2 N}
       local fun {TailFib N Acc Next}
            if N == 0 then Acc else {TailFib N-1 Next Acc+Next}
            end
         end
       in {TailFib N 0 1}
       end
    end

{Show {Fib2 37}}
%Less than 1 sec

%4.
declare X = 0
%a)
declare _|_|X|_|_|nil = ~2|~1|0|1|2|nil
%b)
declare _#_|X#_|nil = 1#2|0#1|nil

%5.
declare fun {Initsegment L1#L2}
       case L1 of
          nil then true
       [] H|T then if L2 == nil then false
               elseif H == L2.1 then {Initsegment T#L2.2} else false
               end
       end
    end

%6.
declare fun {Replace_nth L#N#V}
       if L == nil orelse {Length L}< N then raise 'Incorrect Arguments' end
       elseif N == 0 then V|L.2 else L.1|{Replace_nth L.2#N-1#V}
       end
    end
{Show {Replace_nth (nil)#0#0}}