comp_problem(Vs):-
        D0=[1,2,3,4],
        fd_vector_min_max(-320,320),
        V0 :: D0,
        V1 :: D0,
        V2 :: D0,
        V3 :: D0,
        Vs=[V0,V1,V2,V3],
        conflict_rel(Rel0,[[1,1],[1,2],[2,1],[2,2],[2,3],[3,2],[3,3],[3,4],[4,3],[4,4]],10),
        conflict_rel(Rel1,[[1,1],[1,3],[2,2],[2,4],[3,1],[3,3],[4,2],[4,4]],8),
        conflict_rel(Rel2,[[1,1],[1,4],[2,2],[3,3],[4,1],[4,4]],6),
        conflict_constraint(Rel0,[V0,V1]),
        conflict_constraint(Rel1,[V0,V2]),
        conflict_constraint(Rel2,[V0,V3]),
        conflict_constraint(Rel0,[V1,V2]),
        conflict_constraint(Rel1,[V1,V3]),
        conflict_constraint(Rel0,[V2,V3]),
        true.