listvariant :-
    List = new_list(5),       % create a list of length 5
    nth(1,List,a),            % put an a at position 1 , nth/3 uses indexing from 1
    nth(4,List,b),            % put an b at position 4
    println(list=List),
    append(List,[d],List2),   % append an d at the end , List2 has 5 elements
    println(list2=List2),
    Add = new_list(5),        % create a new list of length 5
    append(List2,Add,List3),  % append 5 free variables to List2
    println(len=List3.len),   % List3 now has 11 elements
    println(list3=List3),
    Value = List3[1],         % get the value at position 1
    println(value=Value).     % will print out a