Add lines of communication diagram | PM Handbook

src/content/docs/project-management-handbook/agile-sprints-profusion-of-terms.mdx

@@ -40,4 +40,6 @@ Our team is the Tech Docs team. We're collectively responsible for docs.newrelic
 
 The primary function of squads is to simplify sprint planning, backlog grooming, and liaisonships. Less people means shorter meetings. It also means better information sharing: The more people you have in a group, the more lines of communication are needed (see illustration) to maintain a shared understanding. Small squads can collaborate more easily than a large team, because not everyone needs to keep in mind everything that goes on everywhere. 
 
-Each squad is responsible for its own grooming and sprint planning, but the managers and scrum masters coordinate grooming to ensure we're meeting our overall goals as a team.
+Each squad is responsible for its own grooming and sprint planning, but the managers and scrum masters coordinate grooming to ensure we're meeting our overall goals as a team.
+
+![Lines of communication scale rapidly as you add people to a team. Where L is Lines and P is People, the formula is L=P((P/2)-0.5)](./images/lines_of_communication.png "Lines of communication versus the number of people on a team.")