(ii) If the IC cards are already specified, we can start from Step 2 to specify the interactions between IC cards.
(iii) If the interactions are already specified, we can start from Step 3 to specify the IC system.
(iii) Specification of context. Some can be absorbed within the IC (i.e. in terms of f and g). But some may be explict, i.e. time, weather,etc.