node_display(N) :- node_state_of(N,S), write(S), nl. start_init(S) :- abolish(start_state,1), asserta(start_state(S)). goal_init(S) :- abolish(goal_state,1), asserta(goal_state(S)). solve(Start,Goal,N,Ans) :- start_init(Start), goal_init(Goal), agenda_init(A), agenda_search(0,N,A,Ans).