cl(1,(member(c,[b,c]):-[member(c,[c])])).
cl(2,(member(d,[b,c,d]):-[member(d,[c,d]),member(d,[d])])).

cl(3,(list([X,Y|T]):-[list([T])])).
cl(4,(list([X,Y,Z|T]):-[list([T])])).

cl(5,(append([1,2],[3,4],[1,2,3,4]) :- [append([2],[3,4],[2,3,4])])).
cl(6,(append([a],[],[a]) :- [append([],[],[])])).