fluents: clogged(T) requires toilet(T). armed(P) requires package(P). unsafe. actions: dunk(P,T) requires package(P), toilet(T). flush(T) requires toilet(T). always: inertial -armed(P). inertial clogged(T). caused -clogged(T) after flush(T). caused clogged(T) after dunk(P,T). caused -armed(P) after dunk(P,T). caused unsafe if not -armed(P). executable flush(T). executable dunk(P,T) if not clogged(T). goal: not unsafe?