At this stage, when the outlines are drawn on computer, there is scope of manipulating the common characters in all letterforms so that it becomes easier when constructing the type.
When you actually see the letterforms placed in a line, a sensitive type designer can definitely see the stress or thrust keylines. Such keylines enhance redability. Every letterform will adhere to at least two keylines, out of which, one will be explicit, and the other implicit.
Here is a sample:
The image below illustrates how the keylines can be defined.