Draw a context diagram, functional decomposition diagram and a level 0 diagram

for the process of buying glasses from the viewpoint of the

patient, but do not bother to identify the steps within each use case. (Just complete the

information at the top of the use case form.) The first step is to see an eye doctor who will

give you a prescription. Once you have a prescription, you go to a glasses store, where you

select your frames and place the order for your glasses. Once the glasses have been made,

you return to the store for a fitting and pay for the glasses.