1. Give examples of translations from DFD descriptions into skeletons of code in some programming language (e.g., the declarative part of an Ada package). You do not need to define algorithms for the translation. 2. Discuss how to define and build modular PNs. 3. Give rules for building complex DFDs by stepwise refinement of higher level ones. 4. Modify the policy of the elevator in the Z specification in by supposing that the highest floor is the VIP floor. Any external request from the VIP floor must be handled with higher priority than any other request.