• Currently, Do_it counts on the slot length being 200. How would you re-write Do_it to inquire the slot length directly from the part? (Hint: You probably need to add a new parameter to the part.)

• Do_it is not foolproof. You can cause problems by setting "B_wid" to 0. How would you fix this flaw? How would you implement general error or range checking in Do_it?

• Could you implement Do_it so that slot size drives intake size? So that either dimension could drive the other?

• Do_it is linked very tightly to this particular drawing. How would you generalize Do_it?