Write a predicate norm_dl(NormalList,DifferenceList) that indicates that both arguments represent the same list.

?- norm_dl([1,2,3,4], A-B).
A = [1, 2, 3, 4|B].

?- norm_dl(A, [1,2,3|[1,2]]-[1,2]).
A = [1, 2, 3] .

?- norm_dl(A, [1,2,3|X]-X).
A = [],     X = [1, 2, 3|X] ;
A = [1],    X = [2, 3|X] ;
A = [1, 2], X = [3|X] ;
A = [1, 2, 3] ;
A = [1, 2, 3, _2966],        X = [_2966|X] ;
A = [1, 2, 3, _2966, _2978], X = [_2966, _2978|X]