module changing_position
  depends on entity_event_and_action

  sort declarations
    orient :: actions
    fidget :: orient

  axioms
    false if instance(X, orient),
             object(X, O),
             -instance(O, tangible_entity).

 
    false if instance(X, fidget),
             -defined_agent(X).

    object(X, Y) if instance(X, fidget),
                    agent(X, Y).