:- ensure_loaded( library(lists) ). % append/3. break_list_on_list( [X|Xs], [X|Ys], [], Rs ) :- append( Ys, Rs, Xs ), !. break_list_on_list( [X|Xs], Ys, [X|Ls], Rs ) :- break_list_on_list( Xs, Ys, Ls, Rs ).