In case you mutually refine several building blocks at once (as proposed in tip 5-25 (mutually refine)), you should explicitly document the origin (aka ancestor or root) of the refined building blocks.

It should be explicit for every element within a refined whitebox where it’s originating (that means, where it is refined from).

You find two examples below:

Document origin by naming convention

Document origin by graphical means

In the next diagram the origin of the refined building blocks is shown by a named rectangle around the refined blocks (for illustration purposes shown in pink color…)